A342-1219-10M-L

TEXAS AGRICULTURAL EXPERIMENT STATION

AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS
W. B. BIZZELL, Presiden!

BULLETIN NO. 256 DECEMBER, 1919

 

DIVISION OF ENTOMOLOGY

TI-IE COWPEA WEEVIL

 

B. YOUNGBLOOD, DIRECTOR,
COLLEGE STATION, muzos COUNTY, TRXAB

STATION STAFFT

ADMINISTRATION

B. YOUNGBLOOD, M. S. Director

A. B. CONNER B. S., Vice Director

J. M. Jonas, A. M.. Assistant Director
CnAs. A. FELKEH, Chief Clerk

A. S. WARE, Secretary .
.............................. .., Executive Assistant i
CHARLES Sosoux, Technical Assistant

VETERINARY SCIENCE
*M. FRANCIS, D. V. M., Chief
H. Scumnr, D. V. S., Veterinarian
D. H. BENNETT, V. M. D., Veterinarian

CHEMISTRY _

G. S. FRAPS, Ph. D., Chief; State Chemist
S. E. AsRURY. M. S., Assistant Chemist
S. LOMANXTZ, B. S., Assistant Chemist

F. B. SCHILLI\G. B. S., Assistant Chemist
J. B. SMITH, B. S., Assistant Chemist

HORTICULTURE
H. NESS, M. S.. Chief
W. S. Horcniuss, Horticulturist

ANIMAL INDUSTRY

J. M. JONES, A. M., Chief; Sheep and Goat
Investigations _

IJ. C. BURNS, B. S., Animal Husbandman in
Charge of Beef Cattle Investigations (on leave)

R. M. Smnwoon, B. S., Poultryman

J. B. McNULTY, B. S., Dairyman

O. E. McComn 1.1., B. S., Animal Husband-
man in Charge of Swine Investigations

G. R. WARREN, B.S., Assistant Animal Hus-

ENTOMOLOGY
M. C. TANQUARY, Ph. D., Chief; State Ento-
mologist
H. J. REINHARD, B. S., Entomologist
H. B. P\RKS, B. S., Apiculturist
———, Assistant Entomologist

 

AGRONOMY
A. B. CoNNER, B. S., Chief
A. H. Lemma, B. S., Agronomist
'. W. GEYER, B. S., Agronomist
. H. LAUDE, M. S., Agronomist

PLANT PATHOLOGY AND PHYSIOLDGV
J. J. TAUBENHAUS, Ph. D., Chief

FEED CONTROL SERVIC
F. D. FULLER, M. S., Chief
J AMES SULLIVAN, Executive Secretary

FORESTRY
E. O. SIECKE, B. S., Chief; State Forester

PLANT BREEDING
E. P. HUMRERT, Ph. D., Chief

FARM AND RANCH ECONOMICS
H. M. ELIOT, M. A., Chief

SOIL SURVEY
**\V. T. CARTER, JR., B. S., Chief
J. F. S-rRoun, Soil Surveyor

bandman T. M. BUSHNELL, B. S., Soil Surveyor
R. A. BRRwFR, B. S., Assistant Animal Hus- W- B. FRANCIS. B- $-. $01! 511F178!!!"
bandman _
SUBSTATIONS
No. l. Beeville, Bee County No. 8. Lubbock, Lubbock County

l. E. COWART, M. S., Superintendent

Troup, Smith County
W. S. Horcnmss, Superintendent

Angleton, Brazoria County
. REYNOLDS, M. S., Superintendent

3.
B
4. Beaumont, Jetferson County
A. H. PRINCE, B. S., Superintendent
l.
T

Temple, Bell County _
. Kmnoucn, B. S., Superintendent

Danton, Denton County
C. H. MCDOWELL, B. S., Superintendent

No. 7. Spur, Dickens County
R. E. DICKSON, B. S., Superintendent _

As of December 1, 1919.

R. E. KARPER, B. S., Superintendent

D. L. JONES. Scientific Assistant

G. M. Rows, Forest Nursergman and Ir-
rigationist

No. 9. Pecos, Reeves County
J. W. JACKSON, B. S., Superintendent

No. 10. (Feeding and Breeding Subltatlnm,
College Station, Brazos County
-—-———-i-—, Superintendent
E. CAMERON, Scientific Assistant

No. ll. Nacogdoches, Nacozdochel County
G. T. McNizss, Superintendent

"No. 12. Chilllcothe, Hardeman County
A. B. CRON, B. S., S

u erintendent
V. E. HAFNER, B. S., cientific Assistant
No. l4.

Sonora, Sutton-Edwgrdl COlllfleI
E. M. PETERS, B. S., Superintendent

In cooperation with School of Agriculture, A. & M. College of Texas.
‘In cooperation wlth the School of Veterinary Medicine, A. 8c M. College 0t Texas.
"In cooperation with the United States Department of Agriculture.

CONTENTS.

PAGE
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9

History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 . . . . . . . . . . . . . . . . . . . . . 9

Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Systematic Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 11

Allied Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

_Gommon Names... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

Economic Importance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13

Food Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.4

Methods of Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14

Life History . . . . . . . .1 . . . . . . . .2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Egg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

Embryology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

Hatching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15

Duration of Egg Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

’ Larva . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . 

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .‘ . . . . . . . . 23

Duration of Larval Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23

Pupa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' . . . . . . . . . . . . . . . . . . . . 30

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3O

Duration of Pupal Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3O

Adults . . . . . . . . . . . . . . . . . ..4 . . . . . ... . . . . . . . . . . . . . . . . . . . . . .. 3'7

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37

Feeding Habits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 38

Average Eggs per Female . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . .. 39

Period from Last Oviposition to Death of Female . . . . . . . . . . . . . . 39

Difference in Death Rate of Sexes . . . . . . . . . . . . . . . . . . . . . . . . . .. 40

Length of Life of Unmated Adults . . . . . . . . . . . . . . . . . . . . . . . . .. 40

Length of Life of Mated Adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Proportion of Sexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 49

Location of Food . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5O

Adaptive Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51

Copulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51

Period Between Maturity and Copulation . . . . . . . . . . . . . . . . . . . .. 52

Fertility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52

Oviposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52

Age at Beginning of Oviposition . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53

Period of Oviposition . . . . . . . . . i . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Rate of Oviposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58

Generation Series . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . .. 78

Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 78

Mortality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Q . . . . . . . . . . . . 80

4 CONTENTS.

PAGE
Natural Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 80

Parasite of Larva . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Parasite of Egg . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . .. 81

Remedial Measures . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . .. 83-

Harvesting . . . . . . . . . . . . . . . . . . .A . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Storage . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . . . . . .  83

Fumigation With Carbon Bisulphide . . . . . . . . . . . . . . . . . . . . . . . .. 84

Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 86

Effect of Heat 0n Germination . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 89

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . .. 90

Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 90

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 91

ILLUSTRATIONS.

PLATES. PAGE

Laboratory where the life history studies were conducted . . . . .. 14
Cowpeas showing extreme Weevil infestation. Egg details are

shown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16

Cowpea Weevil: larva above, pupa below . . . . . . . . . . . . . .  . . .. 23
Cowpea Weevil: adults shoiving variation in size of sex; females

above and males bellow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Parasites: adult larval parasit (a), larval and pupal stage (b),

' and adult egg parasite (c) . . . . . . . . . . . . . . . .., . . . . . . . . .. 81

Fumigator: left, general view; right, detail of door construction 85

FIGURES.
World distribution of the Cowpea Weevil . . . . . . . . . . . . . . . . . . . 10
Distribution of the Cowpea Weevil in the United States . . . . . . . 12

Generation Series Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. '79

[Blank Page in Original Bulletin]

TABLES.

PAGE
Table N0. 1.—Egg Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . .. 15
Table No. 2.—Duration of the Egg Stage . . . . . . . . . . . . . . . . . . .. 16
Table No. 3.—Yearl_v Variation in Duration of Egg Stage . . . . . . . 22
Table No. i-Summary of Duration of the Egg Stage . . . . . . . .. 22
Table No. 5.—Efi’eot of ‘fllemperature on Duration of Egg Stage. . 23
Table No. 6.—Duration of Larval Stage . . . . . . . . . . . . . . . . . . . . .. 23
Table N o. 7.—Yearly Variation in Duration of the Larval Stage. . 29
Table No. 8.——Summary of Duration of the Larval Stage . . . . . .. 29
Table N0. 9.—Efl’ect of Temperature on Length of Larval Stage. . 29
Table No. 10.—Measurements of Pupa . . . . . . . . . . . . . . . . . . . . . . .. 30
Table No. 11.—+Duration of Pupal Stage . . . . . . . . . . . . . . . . . . . . . .. 31
Table No. 12.—Yearly Variation in Duration of Pupal Stage . . .. 36
Table No. 13.—S11mmary of Duration of the Pupal Stage T . . . . . . .. 37

Table N0. 14.—Efl’ect of Temperature on Length of Pupal Stage. 3'7’
Table No. 15.—-Summary of Development of the Cowpea Weevil. . . 3'7

Table No. 16.——Average Eggs per Female . . . . . . . . . . . . . . . . . . . . .. 39
Table No. 1'7.—Average Ilime-Between Oviposition and Death. . .. 40
Table No. 18.——Differenoe in Death Rate of Sexes . . . . . . . . . . . . . .. 110

Table No. 19.——Length of Life of Unmated Adults . . . . . . . . . . . . .. 41

Table No. 20.——Length of Life of Mated Adults . . . . . . . . . . . . . . .. 45

Table No. 2l.—Proportion of Sexes . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Table No. 22.-—Period of Oviposition . . . . . . . . . . . . . . . . . . . . . . . . .. 54

Table No. 23.——-Rate of Oviposition . . . . . . . . . . . . . . . . . . . . . . . . . .. 60

Table N 0. 24.—Fumigation With Carbon Bisulphide . . . . . . . . . . . .. 85

Table N o. 25.—Efl.’ect of Heat on Eg'g, Larval, and Pupal Stages. . 86
Table No. 26.—-Effeot of Heat on Germination . . . . . . . . . . . . . . . . .. 89

[Blank Page in Original Bulletin]

BULLETIN N0. 256. DECEMBER, 1919.

THE COWPEA WEEVIL

*F. B. PAnnocK.
H. J. REINHARD.

INTRODUCTION.

Most Texans who have ever grown cowpeas are familiar with the
cowpea Weevil in at least one of its stages. This insect seems to be
present in every garden and field in the State, wherever any variety
of cowpea is grown. It is a very serious pest, and it is often dreaded

' by those who are growing the cowpea for table use. The climatic

conditions of the State are especially favorable for the development of
the weevil as the mild winters result in a low mortality of the insect
in stored peas, and since the weevil is not generally attached by ene—
mies, its control must depend almost entirely upon the efforts of the
grower. _

The studies recorded in this bulletin were begun by the senior author
in March, 1915, and continued throughout the year. During the spring
and summer of 1916, the life history notes were taken by O. K. Court-
ney, then Assistant Entomologist. The junior author is responsible
for notes made since September, 1916.

HISTORY.

This insect was first described by Fabricus (1) in 1792 from material
collected in Santa Cruz, West Indies. The specimens described were
in his collection at that time, but the date of collection is not given.
The original home of this species is very much in doubt for it was
noted at widely different localities at about the same time. It was
undoubtedly of tropical origin, however, since its spread has been more
or less confined to the tropical and semitropical regions. The next
mention of this species was in 1.795 by Olivier (2) when he records it
as occurring in peas in “Carolina,” which was quite probably Carolina
in Spain, although this cannot be said positively. In 1801, the species
was again listed by Fabricus (3) in a revision of entomology.

The first mention of this species in the United States was by Say (4)
in 1824, recording a specimen from New Orleans, Louisiana. In 1872,
Horn (6) in his “Revision of the Bruchidae of the United States,”
gives the distribution of this species as “West Indies Islands and the
Southern States.” It was not, however, until 1885 ('7) that the insect
attracted attention as an economic pest. In that year, black-eyed “table

beans” from Texas, which were very badly infested with the cowpea

‘Chief, Division of Entomology; State Entomologist; resigned September 15,.

1919.

TEXAS AGRICULTURAL EXPERIMENT STATION.

415w? QSmBQO 23 iv zofinnffiwmmh tic?» A 25F; .

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THE COWPEA WEEVIL. 11

weevil, B. quadrimaculatus, were exhibited at the Cotton Exposition in
Atlanta, Georgia.

It was not until 1893 (8) that this species again attracted attention,
being found in large numbers in beans exhibited by Brazil and Vene-
zuela at the World’s Fair in Chicago. At this time the Bureau of
Entomology records the species as “common in Southern States.” The
same year the Weevil was reported from Delaware (9) in peas that had
been purchased from North Carolina. It was also introduced into New
York that year (10) in peas sent from the South, the exact locality
of the origin of the peas not being given. The following year it was
reported from Georgia, Mississippi, Alabama, and Texas. Hamilton

(1.1) in his “Distribution of Coleoptera” lists southern France and -

Ethiopia as the habitat of this species. In 1895 it Was reported from
Ames, Iowa (12) in seed purchased from Virginia. In 1896 Chit-
tenden (13) added British Honduras, Mexico, and Italy, to the dis-
tribution of the pest and the following year he added the East Indies
and Sierra Leone to its domain. Finally in 1916, a report from Wis-
consin indicated the presence of the cowpea weevil in the Northwest,
where it had been introduced from the South in seed.

DISTRIBUTION.

In Figure 1 is shown the distribution of the cowpea weevil, as indi-
cated in the available references on this species, but from all the
available information it is impossible to ascertain the date of the en-
trance of this species into the United States or the exact place and
manner of its introduction. Nor can the spread of the species be
traced from state to state, though it is certain that it is confined by
the range of its only food plant, the cowpea, to the Southern States.
(See Figure 2.) The weevil has been introduced many times with
seed into the Northern States, but. has not become established in such
locations, and it does not even occur in California or other Western
States.

SYSTEMATIC POSITION.

In his original description, Fabricus places this species in the genus
Bruchus, erected by Linnaeus in 1767’. Fabricus defined the genus as
follows: Palpi aequales, filiformes; maxilla vnembrancea, bilfida;
labiwm aczcminatzrm; antennae filiformes. Say in 1824 lists B.
quadrimrzculatus in the Curculiomides although no reason is given for
changing from the arrangement of Fabricus. In LeConte’s revision
(5) of this Work in 1853 he criticizes the “unnatural classification of
this family.” Horn, in 187.2, places this species in the genus Bruchus,
in his revision o-f the Bruchidae of theUnited States. In 1894-, Hamil-
ton in his “Catalogue of Coleoptera,” lists quadrimaculatus in the genus
Bruchus, of the family’ Bruchidae. Chittenden, in 1897, places quadri-
maculaius in the genus Bruchus. Blatchley, in 1910, in his “Coleoptera
of Indiana,” places quad/rinmculatus‘ in the genus Bmchus of the family
Bruchida-e.

12 TEXAS AGRICULTURAL EXPERIMENT STATION.

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THE COWPEA WEEVIL. 13

ALLIED SPECIES.

The most closely related species,both from the anatomical and his-
torical standpoint, i.s B. chmensis Linn. This species is separated from
quadrimaculatzas as follows:

b. Median basal thoracic lobe with elevated ivory-like spgce:
chinensis.

bb. Median basal thoracic lobe with whitish hairs only: quadri-
maculatus.

These species are confused very often by those who are not specialists
in this group. Both of these species feed extensively on the cowpea,
and their life history, habits, and control are quite similar. Horn (6)
gives the following points wherein B. quadrimaculatus differs from
chinensis: -

“The thorax is broader, the sides distinctly arcuate, the basal lobe
not eburneous. The scutellum is fiat and with a median line. The
elytra are longer, and differently spotted and the abdomen is evenly
clothed with cinereous pubescence. This species is also larger and
much less robust.”

COLIMON NAME.

The usual name that has been applied to the insect in previous
literature is the “four spotted bean weevil.” In 1897, Chittenden says,
the above name (the cowpea weevil), which is proposed for Bruchus
chineensis, will sufficiently distinguish it from B. quadrimaculatus, since
the latter is already known as the “four spotted bean weevil.” When
the studies here recorded were begun on the weevils infesting cowpeas
in this State, it was thought that B. ch/inensis was by far the more
abundant species. Collections, however, made over a period of three
years from all sections of the State show that quadrimaculatus is much
the more common. Bruchus quadrimaculatus was used in all of the
experiments. For our purpose in Texas, then, in spite of the fact that
the double use of aicommon name may prove confusing, the cowpea
weevil must be known as B. quadrimaculatus. ‘

ECONOMIC IMPORTANCE.

In view of the fact that the cowpea is grown very extensively in
Texas, that human food as well as stock food is concerned, and that the
weevil is present in every section where the cowpea is grown, it becomes
evident that the damage done by this insect is very great and materially
affects the agricultural economy of the State. The pest became of
paramount importance when the treatment of the black-eyed cowpea for
export trade was commenced. 'I‘his variety of cowpea is especially sus-
ceptible to infestation by the weevil, and very few cowpeas are harvested
which are not infested. The treatment of such cowpeas presented a
very difficult problem and they were therefore, even after treatment,
unfit for human consumption. The keeping of cowpea seed has always
been a very diflicult problem, since the germination percentage of
weevil-infested seed is always very low. The importance of the weevil
in Texas is indeed very great although it is difficult to place a money

'14; Texas AGRICULTURAL EXPERIMENT STATION.

value on the damage done. The cowpea is an important crop, but its
value in the State is limited by the work of the weevil. There is hardly
a grower Who does not have to reckon with. the ravages of this pest.
when considering the production of cowpeas.

U
FOOD PLANTS.

The primary food plant for this insect, as the common name indi-
cates, is the cowpea. Apparently all varieties of cowpeas are attacked
and the insect shows no preference for any particular variety. It has
been repeatedly bred in the following varieties of cowpeas: Black-eyed,
Old Bokhara, Chinese Red,_Clii11ese~ Yellow, Red Ripper, Iron, Speckled
Cowder, Whippoorwill, Tinkles Holstein, New Era, and Lady Pea.
The cowpea weevil has not been observed to feed upon any plant except

the cowpea. Laboratory experiments have failed t0 establish any of

the following as food plants for this insect: Navy beans, Mexican

Frijole, Lima or butter beans, soy beans, yellow string beans, castor

beans, and peanuts. Oviposition proceeded without reduction or delay,
but in each case the eggs either tailed to hatch or the young larvae
perished before entrance into the substituted food supply was ac-
complished. The active feeding period is confined to the larval stage
and it is doubtful if any other plants can be added to the cowpea, as a
food for this insect.

IVIETHODS OF STUDY.

For the detailed observations on the life history of the weevil, vials
2524100 mm. were used. A pair of weevils were placed in these with
ample peas for oviposition for a 24-hour period. The Chinese Red
cowpea was used because any eggs on them were easy to observe. The
peas with eggs upon them were removed each day and observations
were made on the hatching of the egg, the pupation of the larvae, and
the emergence of the adult. The laboratory, in which all life history
observations were made, is shown in Plate 1.. No heat was available
in the laboratory so that conditions were very similar to warehouse or
storage conditions. Temperature records were obtained by the use of
a recording thermograph placed close to the vials containing the
weevils in any stage. In some phases of the work, humidity records
were obtained also. by the use of a. hygro-thermograph. Seasonal’ notes
were made in the field on the Agronomy Farm and in the experimental
plats of the Division of Entomology.

LIFE HISTORY.

The life history of the cowpea weevil has been mentioned by a few
of the early writers in a very indefinite way. In 1891, Slingerland
(10) made some laboratory notes on the egg stage and the habits of
the adults. In 1895, Osborn (12) describe-d all the stages and deter-
mined the length of the egg stage. Later papers on weevils assume
that the life history of B. quadrimaculatus is very much like that of
chinensis, obteciits, or pest. In the following pages are given the re-
sults of our detailed observations on all phases of its life history.

wimfim  fimvogfioww Qrmwm $5 Him wfiwfioww wffifimm émwm oosmcgmm.

THE CowPnA WEEVIL. 15

From these results it is evident that thelife history of the cowpea
Weevil is not composed of definite seasonal broods. The records show

that there is a continuous breeding when food is available, and at this '

locality there is seldom a cessation of activity. Climatic conditions
‘undoubtedly do restrict the abundance of individuals at certain. seasons.
The generation series was conducted to determine the number of gen-
erations of the weevils that may normally occur in a period of twelve

months.
The Egg.

The outline of the egg is generally ovate, varying somewhat at times.
Its length is usually one and one-third times its breadth, the posterior
end broadly rounded, the anterior end tapering, giving the semblance
of a point when viewed with the unaided eye. Under the microscope
it likewise appears rounded but much less broad than the posterior
end. Viewed laterally the egg is convex in outline, higher at the
posterior, sloping sharply toward the anterior end. The whole under
surface of the egg is attached to the pea. except in some abnormal cases
when the female is nearing the end of her quota of eggs. Apparently
the supply of sticky material withwhich the eggs are glued to the
peas is exhausted and in such cases the eggs are insecurely fastened to
the pea, either on the end or the side. Such eggs have never been
observed to hatch. When first laid the egg is glistening white, jellylike,
translucent mass, but soon hardens on exposure to the air. The sur-
face is perfectly smooth and shining. Plate II‘ shows details of the
eggs when deposited under natural conditions. The size of the egg
varies greatly; measurements of the greatest length and width of eggs
gave the figures in Table 1.

Table 1.—Egg Measurements.

Length Width
1 . . . . . . . . . . . . . . . . . . . . . . .. 1.98 mm. 1.38 mm

2 . . . . . . . . . . . . . . . . . . . . . . .. 2.64 mm. 1.44 mm

3 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.35 mm

4 . . . . . . . . . . . . . . . . . . . . . . .. 2.63 mm. 1.45 mm

5 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.37 mm

6 . . . . . . . . . . . . . . . . . . . . . . .. 2.59 mm. 1.46 mrn

7 . . . . . . . . . . . . . . . . . . . . . . .. 2.48 mm; 1.80 mm

8 . . . . . . . . . . . . . . . . . . . . . . .. 2.49 ‘mm. _ 1.54 mm

9 . . . . . . . . . . . . . . . . . . . . . . .. 2.57 mm. 1.45 mm

10 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.39 mm

11 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.45 mm

12 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.36 mm

13 . . . . . . . . . . . . . . . . . . . . . . .. 2.64 mm. 1.35 mm

14 . . . . . . . . . . . . . . . . . . . . . . .. 2.53 mm. 1.47 mm

15 . . . . . . . . . . . . . . . . . . . . . . .. 2.40 mm. 1.34 mm

Embry0Z0gy.——As the developing embryonic larva increases in size,
its movements can be very readily detected through the upper part of
the egg shell, which remains white and translucent until it is hatched.
When matured, with its brown head appearing as a tiny speck near the
broader end of the egg, the larva soon begins to eat its way through
the egg shell.

Hatchmg.—The exit is always made 011 the side of the egg which is
attached or glued to the pea. The larva, having eaten through the

16 TEXAS AGRICULTURAL EXPERIMENT STATION.

shell of the egg and reached the surface of the pea, continues to eat its
way into the pea Without any apparent delay. The exit hole in the egg
shell and the entrance aperture into the pea are very tiny and can
hardly be distinguished Without magnification. The hole in the egg
shell and the entrance hole in the pea, are very nearly round and
have a smooth edge. The exit hole in the egg shell is always at the
broad end of the egg, the aperture by which the larva gains entrance
into the pea always appearing directly beneath it. 7

As soon as hatching begins, the color of the egg is changed materially.
It first becomes mottled ivith dark yellowish opaque spots, because as
the larva feeds, many small particles of food, together with the excreted
material, are pushed back under the egg shell. By the time the larva
has completely entered the pea, the entire space beneath the egg shell is
filled with this material and the egg then is a uniform yellow or straw
color, and is wholly opaque. g _

The length of the hatching period varies considerably, depending
upon the temperature and the hardness or dryness of the peas. In
fresh‘ peas the period of hatching may comprise only the short period
of an hour or two, while several days may elapse before the larva suc-
ceeds in entering dried and hardened peas.

Table 2.—Duration of the Egg Stage.

_ Temperature
Laid Hatched Period
‘ Max. Min. Mean
Nov. 7 . . . . . . . . . . . . 6 81 66 76.0

Nov. 8 . . . . . . . . . . .. 6 81 66 75.0 '

Nov. 9 . . . . . . . . . . . . 6 82 66 75. 1

Nov. 10 . . . . . . . . . . . . 6 83 74 76.2

Nov. 11 . . . . . . . . . . .. _ 6 83 , 74 75.4

Nov. 12 . . . . . . . . . . . . 6 83 64 64.2

Nov. 12 . . . . . . . . . . . . 4 83 64 77.2

Nov. 17 . . . . . . . . . . . . 8 83 54 70.2

Nov. 18 . . . . . . . . . . . . 8 84 57 69.7

Nov. 18 . . . . . . . . . . .. 7 82 57 68.5

Nov. 19 . . . . . . . . . . .. 7 84 57 69.5

Nov. 20 . . . . . . . . . . . . 7 84 57 70.8

Nov. 21 . . . . . . . . . . . . 7 86 57 72.0

Nov. 22 . . . . . . . . . . . . 7 87 58 73.5

Nov. 23 . . . . . . . . . . . . 7 87 66 75.7

Nov. 24 . . . . . . . . . . . . 7 87 66 76.3

Nov. 25 . . . . . . . . . . . . 7 87 66 76.0

Nov. 26 . . . . . . . . . . . . 7 87 66 65.5

Nov. 27 . . . . . . . . . . . . 7 87 66 76.2

Nov. 28 . . . . . . . . . . . . 7 87 66 76. 1

Nov. 29 . . . . . . . . . . . . 7 82 66 76.1

Nov. 29 . . . . . . . . . . . . 6 82 70 75.6

Nov. 30 . . . . . . . . . . . . 6 82 70 76.0

Dec. . . . . . . . . . . . . 6 86 68 76. 5

Dec. 3 . . . . . . . . . . . . 7 86 68 77.0

Dee. 3 . . . . . . . . . . . . 6 8b 68 76.7

Dec. 4 . . . . . . . . . . . . 6 86 67 76.8

Dec. 5 . . . . . . . . . . . . 6 86 67 76.5

Dec. 6 . . . . . . . . . . . . 6 86 67 77.5

Dec. 7 . . . . . . . . . . . . 6 85 67 77.6

Dec. 8 . . . . . . . . . . . . 6 85 67 77.3

Dec. . . . . . . . . . . . . 6 85 67 76.2

Dee. 10 . . . . . . . . . . .. 6 85 57 75.7

Dec. 11 . . . . . . . . . . .. 6 83 50 74.9

Dec. 12 . . . . . . . . . . .. 6 83 43 71.8

Dee. 13 . . . . . . . . . . .. 6 83 43 69.1

Jan. 4 . . . . . . . . . _ . . 27 83 29 55.8

Jan 5 . . . . . . . . . . . . 27 83 29 55.4

Jan 6 . . . . . . . . . . . . 27 79 29 55.6

Jan 7 . . . . . . . . . . . . 27 79 29 55.6

Jan 8 . . . . . . . . . . . . 27 79 29 55.4

Jan 7 . . . . . . . . . . . . 25 79 29 55.2

Jan 7 . . . . . . . . . . . . 24 79 29 55.2

Jan. 7 . . . . . . . . . . .. 23 79 29 55.3

Plate II. Cowpeas showing extreme weevil infestation. Egg details are shown.

[Blank Page in Original Bulletin]

THE COWPEA WEEVIL.

Table 2.——Duration of the Egg Stage.-—Continued.

17

Temperature
Laid Hatched Period _
hdax hdny hdean
79 29 55.0
79 29 54.0
79 29 54.2
79 29 55.5
79 29 55.8
79 29 ' 56.4
79 22 54.0
79 29 53.4
79 29 57.9
79 22 58.5
79 45 61.0
79 45 61.8 '
. 79 45 62.0
. 79 22 53.1
. 79 22 60.5
. 79 22 53.4
. 79 22 53.2
. 79 22 51.9
. 78 26 54.5
. 78 26 54.3
. 81 38 57.8
. . 81 39 59.3
. . 81 39 59.3
. . 81 39 59.7
; . 81 39 59.3
. . 86 39 59.3
. . 86 39 61.2
. . 86 39 61.7
. . 86 39 61.4
. . . 86 39 63.2
. . 86 44 64.2
. .1 86 44 64.1
. . 86 44 69.2
. . 89 44 68.0
. . 89 44 68.2
. . 89 48 70.9
. . 89 48 70.7
. . 89 48 64.0
. . 89 48 68.8
. . 89 48 -69.9
. ' 86 48 69.4
. ' 86 48 68.4
. 1 86 48 67.0
. ' 86 40 65.4
. ' 86 40 64.2
. 1 86 40 64.1
. ' 83 40 64.4
. ' 83 40 64.0
. 1 83 40 ~64.1
' ' 83 40 62.3
1 ‘ 83 40 63.7
' 1 83 40 64.1
' ' 83 40 65.0
‘ ' 83 40 65.0
Apfll 7 . . . . . . . . . . . .. Aprfl15 8 83 40 64.5

Aprfl 8 . . . . . . . . . . . .. Aprfl16 . . . . . . . . . . .. 8 83 40 66.2

Apfll10 . . . . . . . . . . . .. Apfll16 . . . . . . . . . . .. 6 83 53 70.4

Aprfl . . . . . . . . . . . H AprU17 . . . . . . . . . . .. 6 85 56 71.1

Apfl]12 . . . . . . . . . . . .. Aprfl18 . . . . . . . . . . .. 6 87 56 71.5

Apfil13 . . . . . . . . . . . .. Apfil20 . . . . . . . . . . .. 7 87 56 72.7

Apflll . . . . . . . . . . . .. Aprfl21 . . . . . . . . . . .. 7 87 56 72.5

Aprfl15 . . . . . . . . . . . .. Aprfl . . . . . . . . . . .. 7 87 56 71.5

Apflllfi . . . . . . . . . . . .. AprU2 . . . . . . . . . . .. 7 87 58 71.4

Apfil17 . . . . . . . . . . . .. Aprfl24 . . . . . . . . . . .. 7 87 58 73.4

Apfll18 . . . . . . . . . . . .. Aprfl . . . . . . . . . . . .. 7 87 58 75.0

Apfll19 . . . . . . . . . . . .. Apfll25 . . . . . . . . . . .. 6 87 58 74.8

Apfil20 . . . . . . . . . . . .. Apfil26 . . . . . . . . . . .. 6 87 58 74.0

Apfll21 . . . . . . . . . . . H Aprfl . . . . . . . . . . .. 8 87 52 71.6

Apfil22 . . . . . . . . . . . . .. A rfl30 . . . . . . . . . . .. 8 87 52 70.8

Apfil23 . . . . . . . . . . . .. ay 1 . . . . . . . . . . .. 8 87 52 70.4

Apfil2 . . . . . . . . . . . .. hday 3 . . . . . . . . . . .. 9 87 52 70.5

AprH25 . . . . . . . . . . . . .. hday 4 . . . . . . . . . . .. 9 87 52 69.7

Apfll26 . . . . . . . . . . . .. hday 4 . . . . . . . . . . .. 8 86 52 69.2

AprH2 . . . - . . . . . . . . . A. hday 4 . . . . . . . . . . .. 7 86 52 68.2

Apfll28 . . . . . . . . . . . . .. hday 4 . . . . . . . . . . .. 6 86 54 68.8

A fil30 . . . . . . . . . . . .. hday 6 . . . . . . . . . . .. 6 94 65 73.9

ay . . . . . . . . . . . .. hday 6 . . . . . . . . . . .. 5 94 65 74.2

Lday 2 . . . . . . . . . . . . .. hday 8 . . . . . . . . . . .. 6 99 65 77.7

a

18 TEXAS AGRICULTURAL EXPERIMENT STATION.
Table 2.—Duration of the Egg Stage.-—Continued.
_ Temperature
Laid Hatched Perlod
Max Min. Mean
1916
May 3 . . . . . . . . . . . .. May 8 . . . . . . . . . . . . 5 99 66 79.2

May 4 . . . . . . . . . . . . . . May 9 . . . . . . . . . . . . 5 100 73 82. 1

May 5 . . . . . . . . . . . . . May 10 . . . . . . . . . . . . 5 100 74 86.3

May 6 . . . . . . . . . . . .. May 11 . . . . . . . . . . . . 5 100 76- 87.6

May 7...._. . . . . . . .. May 12 . . . . . . . . . . .. 5 100 80 88.6

May 8 . . . . . . . . . . . . .. May 13 . . . . . . . . . . . . 5 100 80 89.2

May 9 . . . . . . . . . . . . . . May 14 . . . . . . . . . . .. 5 98 8O 88.9

May 10 . . . . . . . . . . . .. May 15 . . . . . . . . . . .. 5 98 80 88.7

May 11 . . . . . . . . . . . .. May 16 . . . . . . . . . . .. 5 97 74 88.4

May 12 . . . . . . . . . . . .. May 19 . . . . . . . . . . .. 7 97 70 84.7

May 13 . . . . . . . . . . . . . May 20 . . . . . . . . . . . . 7 97 70 82.5

May 14 . . . . . . . . . . . .. May 21 . . . . . . . . . . .. 7 97 70 81.1

May 15 . . . . . . . . . . . .. May 22 . . . . . . . . . . .. 7 97 70 80.3

May 16 . . . . . . . . . . . .. May 23 . . . . . . . . . . .. 7 91 70 79.1

May 17 . . . . . . . . . . . .. May 24 . . . . . . . . . . .. 7 91 70 78.7

May 18 . . . . . . . . . . . .. May 24 . . . . . . . . . . .. 6 91 70 78.5

May 19 . . . . . . . . . . . . . May 25 . . . . . . . . . . .. 6 91 71 79.1

May 2O . . . . . . . . . . . .. May 26 . . . . . . . . . . .. 6 91 71 80.2

May 21 . . . . . . . . . . . . . May 27 . . . . . . . . . . .. 6 89 71 81.8

May 22 . . . . . . . . . . . . . May 26 . . . . . . . . . . . . 4 89 71 80.0

May 23 . . . . . . . . . . . .. May 28 . . . . . . . . . . .. 5 89 71 80.9

May 24 . . . . . . . . . . . . . May 29 . . . . . . . . . . . . 5 89 73 80.5

May 25 . . . . . . . . . . . . . May 30 . . . . . . . . . . . . 5 89 73 80.7

May 26 . . . . . . . . . . . .. May 31 . . . . . . . . . . .. 5 94 73 81.0

May 27 . . . . . . . . . . . .. June 1 . . . . . . . . . . .. 5 94 73 81.6

May 28 . . . . . . . . . . . . . June 2 . . . . . . . . . . . . 5 94 73 82.0.

May 29 . . . . . . . . . . . .. June 2 . . . . . . . . . . .. 4 94 74 82.5

May 30 . . . . . . . . . . . . . June 3 . . . . . . . . . . . . 4 94 77 83.5

May 31 . . . . . . . . . . . .. June 4 . . . . . . . . . . .. 4 91 77 84.3

June 1 . . . . . . . . . . . .. June 5 . . . . . . . . . . .. 4 92 78 84.1

June 2 . . . . . . . . . . . .. June 6 . . . . . . . . . . .. 4 93 78 84.2

June 3 . . . . . . . . . . . .. June 7.. 4 94 78 84.8

June 4 . . . . . . . . . . . . .. June 8 . . . . . . . . . . .. 4 94 71 84.8

June 5 . . . . . . . . . . . .. June 9 . . . . . . . . . . .. 4 94 71 82.4

June 6 . . . . . . . . . . . .. June 10 . . . . . . . . . . .. 4 94 71 81.7

June 7 . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 4 90 71 81.6

June 8 . . . . . . . . . . . . .. June 12 . . . . . . . . . . .. 4 90 72 81.5

June .9 . . . . . . . . . . . . . . June 13 . . . . . . . . . . . . 4 90 73 83.6

June 10 . . . . . . . . . . . .. June 14 . . . . . . . . . . .. 4 9O 76 84.0

June 11 . . . . . . . . . . . .. June 15 . . . . . . . . . . .. 4 9O 76 83.7

June 12 . . . . . . . . . . . .. June 16 . . . . . . . . . . .. 4 90 72 83.3

June 13 . . . . . . . . . . . .. June 17 . . . . . . . . . . .. 4 90 72 82.0

June 14 . . . . . . . . . . . . .. June 18 . . . . . . . . . . .. 4 89 72 82.0

June 15 . . . . . . . . . . . .. June 19 . . . . . . . . . . .. 4 89 72 81.0

June 16 . . . . . . . . . . . . .. June 20 . . . . . . . . . . .. 4 91 74 80.5

June 17 . . . . . . . . . . . . .. June 21 . . . . . . . . . . .. 4 95 75 81.7

June 18 . . . . . . . . . . . .. June 22 . . . . . . . . . . .. 4 95 75 83.0

June 19 . . . . . . . . . . . .. June 23 . . . . . . . . . . .. 4 95 75 84.5

June 2O . . . . . . . . . . . .. June 24 . . . . . . . . . . .. 4 95 78 ‘ 85.5

June 21 . . . . . . . . . . . . .. June 25 . . . . . . . . . . .. 4 95 80 86.2

June 22 . . . . . . . . . . . . . June 26 . . . . . . . . . . . . 4 95 80 86.7

June 23 . . . . . . . . . . . . . June 27 . . . . . . . . . . . . 4 95 80 86.7

June 24 . . . . . . . . . . . . . une 28 . . . . . . . . . . . . 4 95 75 87.7

June 25 . . . . . . . . . . . . . . June 29 . . . . . . . . . . . . 4 95 75 87.5

June 26 . . . . . . . . . . . . . June 30 . . . . . . . . . . . . 4 95 75 86.2

June 27 . . . . . . . . . . . . .. July 1 . . . . . . . . . . .. 4 95 75 85.2

June 28 . . . . . . . . . . . .. July 2 . . . . . . . . . . .. 4 93 76 84.0

June'29 . . . . . . . . . . . .. July‘ 3 . . . . . . . . . . .. 4 93 77 84.2

June 30 . . . . . . . . . . . . .. July 4 . . . . . . . . . . .. 4 93 76 84.5

July 1 . . . . . . . . . . . . . July 5 . . . . . . . . . . . . 4 95 76 84.7

July 2 . . . . . . . . . . . .. July 6 . . . . . . . . . . .. 4 95 76 85.2

July 3 . . . . . . . . . . . .. July 7 . . . . . . . . . . .. 4 97 76 85.5

July 4 . . . . . . . . . . . . .. July 8 . . . . . . . . . . .. 4 a 99 77 86.5

July 5 . . . . . . . . . . . .. July 9 . . . . . . . . . . .. 4 99 79 88.0

July 6 . . . . . . . . . . . . . July 10 . . . . . . . . . . .. 4 99 79 88.5

July 7 . . . . . . . . . . . .. July 11 . . . . . . . . . . .. 4 99 79 89.2

July 8 . . . . . . . . . . . . .. July 12 . . . . . . . . . . .. 4 98 79 89.0

July 9 . . . . . . . . . . . .. July 13 . . . . . . . . . . .. 4 98 79 85.2

July 10 . . . . . . . . . . . .. July 14 . . . . . . . . . . .. 4 97 79 87.0

July 11 . . . . . . . . . . . .. July 15 . . . . . . . . . . .. 4 95 80 86.5

July 12 . . . . . . . . . . . .. July 16 . . . . . . . . . . .. 4 97 79 86.2

Julv 13 . . . . . . . . . . . .. July 17 . . . . . . . . . . .. 4 98 79 87.0

July 14 . . . . . . . . . . . .. July 18 . . . . . . . . . . .. 4 99 78 87.5

July 15 . . . . . . . . . . . .. July 19 . . . . . . . . . . .. 4 99 78 88.2

July 16 . . . . . . . . . . . .. July 20.. 4 99 78 87.7

July 17 . . . . . . . . . . . .. July 21 . . . . . . . . . . .. 4 99 78 88.0

July 18 . . . . . . . . . . . .. July 22 . . . . . . . . . . .. 4 97 80 87.7

July 19 . . . . . . . . . . . .. July 23 . . . . . . . . . . .. 4 97 80 88.2

July 20 . . . . . . . . . . . .. July 24 . . . . . . . . . . .. 4 99 80 88.2
I

THE COWPEA WEEVIL.

Table 2.—Duration 9f "the Egg Staga-Continued.

19

Tempera Lvrc

Laid Hatched Period -—
hdax A111. hdcan
4 99 80 88.5
4 99 78 89.0
4 99 78 87.7
4 98 78 87.5
4 97 78 86.7
4 97 78 86.2
4 97 78 86.0
4 97 78 86.0
4 97 78 86.5
4 97 79 86.5
4 97 79 87.5
4 97 79 88.0
4 97 79 88.2
4 96 79 86.5
4 96 79 85.5
4 95 79 85.5
4 95 79 84.2
4 95 79 84.7
4 94 78 85.0
4 95 78 85.0
4 96 80 85.7
4 95 79 87.0
4 95 79 87.2
4 95 75 87.0
4 95 75 85.7
4 95 75 85.5
4 94 75 85.7
4 100 80 85.7
4 100 80 87.7
4 100 80 88.5
4 100 79 88.7
4 97 73 88.2
4 96 70 85.7
4 93 70 84.2
4 93 70’ 83.0
4 94 70 83.2
4 94 75 84.2
4 97 77 85.0
4 97 77 86.0
4 97 77 86.0
4 97 78 86.5 '
4 97 79 87.2
3 97 80 87.0
4 97 80 88.2
4 97 80 88.5
4 101 80 88.5
4 101 80 89.0
4 101 80 89.5
4 101 80 89.2
4 99 80 89.0
3 97 70 88.5
4 97 78 88.2
4 97 73 87.5
4 97 70 85.7
5 99 67 82.4
5 99 67 81.4
5 99 67 80.0
5 99 67 79.6
5 99 67 80.2
4 91 68 80.5
4 91 69 80.0
4 91 70 80.5
5 91 70 81.0
5 105 70 80.2
5 105 71 80.2
5 105 60 83.4
6 105 57 79.3
6 105 57 76.6
6 95 57 76.4
6 85 57 74.0
6 89 57 72.6
6 89 59 73.5
5 89 54 74.0
5 89 66 77.0
5 90 66 77.7
4 90 66 77.7
4 91 69 78.0
4 94 68 79.3
4 94 68 81.0

TEXAS ‘AGRICULTURAL EXPERIMENT STATION.

20
Table 2.—Duration of the Egg Stage.-—-Continued.
_ Temperature
Laid Hatched Penod
Max Min. Mean
1916
Oct. 8 . . . . . . . . . . . . . . Oct 12 . . . . . . . . . . . . 4 94 68 80.0

Oct. 9 . . . . . . . . . . . . . Oct 13 . . . . . . . . . . . . 4 94 68 79.5

Oct. 1O . . . . . . . . . . . . . Oct 14 . . . . . . . . . . . . 4 9O 68 79. 7

Oct. 11 . . . . . . . . . . . . . Oct 15 . . . . . . . . . . . . 4 90 68 79.7

Oct. 12 . . . . . . . . . . . . . Oct 16 . . . . . . . . . . . . 4 9O 65 80.0

Oct. 13.. Oct 18 . . . . . . . . . . . . 5 90 61 78.8

Oct. 14 . . . . . . . . . . . . . Oct 22 . . . . . . . . . . . . 8 87 41 70. 6

Oct. 15 . . . . . . . . . . . . . . Oct 23 . . . . . . . . . . . . 8 87 41 68.6

Oct. 16 . . . . . . . . . . . . . Oct 25 . . . . . . . . . . . . 9 95 41 69.0

Oct. 17 . . . . . . . . . . . . . Oct 27 . . . . . . . . . . . . 10 95 41 68.4

Oct. 18 . . . . . . . . . . . . . Oct 28 . . . . . . . . . . . . 10 95 41 68.1

Oct. 19 . . . . . . . . . . . . . Oct 28 . . . . . . . . . . . . 9 95 41 68.3

Oct. 20 . . . . . . . . . . . . . . Oct 29 . . . . . . . . . . . . 9 95 41 68.5

Oct. 21 . . . . . . . . . . . . . Oct 29 . . . . . . . . . . . . 8 95 52 69.3

Oct 22 . . . . . . . . . . . . . . Oct 30 . . . . . . . . . . . . 8 . 95 53 71.3

Oct 23 . . . . . . . . . . . . . Oct 3O . . . . . . . . . . . . 7 95 53 72.4

Oct 24 . . . . . . . . . . . . . Nov 1 . . . . . . . . . . . . 8 9O 53 74. 6

Oct 25 . . . . . . . . . . . . . . Nov 2 . . . . . . . . . . . . 8 9O 53 74.1

Oct 26 . . . . . . . . . . . . . Nov 2 . . . . . . . . . . . . 7 90 53 74.0

Oct 27 . . . . . . . . . . . . . Nov 2 . . . . . . . . . . . . 6 9O ‘ 56 75.6

Oct 28 . . . . . . . . . . . . . Nov 3 . . . . . . . . . . . . 6 9O 6O 76.2

Oct 29 . . . . . . . . . . . . . Nov 4 . . . . . . . . . . . . 6 9O 6O 77.6

Oct 3O . . . . . . . . . . . . . Nov 5 . . . . . . . . . . . . 6 89 6O 77.4

Oct 31 . . . . . . . . . . . . . Nov 6 . . . . . . . . . . . . 6 89 60 76.6

Nov 1 . . . . . . . . . . . . . Nov 7 . . . . . . . . . . . . 6 89 60 75.1

Nov 2 . . . . . . . . . . . . . Nov 8 . . . . . . . . . . . . 6 87 6O _ 75.5

Nov 3 . . . . . . . . . . . .. Nov 11 . . . . . . . . . . .. 8 87 51 74.5

Nov 4 . . . . . . . . . . . .. Nov 12 . . . . . . . . . . .. 8 87 51 73.8

Nov 5 . . . . . . . . . . . .. Nov 16 . . . . . . . . . . .. 11 87 33 68.1

Nov 6 . . . . . . . . . . . .. Nov 19 . . . . . . . . . . .. 13 89 33 66.0

Nov 7 . . . . . . . . . . . .. Nov 20 . . . . . . . . . . .. 13 93 33 65.6

Nov. 8 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . . . 13 94 33 65.4

Nov. 9 . . . . . . . . . . . . . Nov 25 . . . . . . . . . . . . 16 94 33 64.6

Nov. 10 . . . . . . . . . . . .. Nov 26 . . . . . . . . . . .. 16 94 33 64.1

Nov. 11 . . . . . . . . . . . .. Nov 27 . . . . . . . . . . .. 16 94 33 64.0

Nov. 12 . . . . . . . . . . . .. Nov 28 . . . . . . . . . . .. 16 94 33 63.7

Nov. 13 . . . . . . . . . . . . . Nov 29 . . . . . . . . . . .. 16 98 33 63.1

Nov. 14 . . . . . . . . . . . . . Nov 29 . . . . . . . . . . . . 15 98 33 63.0

Nov. 15 . . . . . . . . . . . .. Nov 3O . . . . . . . . . . .. 15 98 39 65.3

Nov. 16 . . . . . . . . . . . . . Nov 3O . . . . . . . . . . . . 14 98 44 66.7

Nov. 17 . . . . . . . . . . . .. Dec 1 . . . . . . . . . . .. 14 98 44 68.1

Nov._ 18 . . . . . . . . . . . .. Dec 1 . . . . . . . . . . . . 13 98 44 68.3

Nov. 19 . . . . . . . . . . . . . Dec 2 . . . . . . . . . . . . 13 98 44 69.0

Nov. 20 . . . . . . . . . . . . . Dec 3 . . . . . . . . . . . . 13 98 44 69.3

Nov. 21 . . . . . . . . . . . .. Dec 4 . . . . . . . . . . . . 13 98 44 69.8

Nov. 22 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . .. 13 101 44 69.3

Nov. 23 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 12 101 44 72.0

Nov. 24 . . . . . . . . . . . . . Dec 6 . . . . . . . . . . .. 12 101 44 73.0

Nov. 25 . . . . . . . . . . . . . Dec 6 . . . . . . . . . . .. 11 101 44 73.6

Nov 26. Dec 6 . . . . . . . . . . .. 10 101 48 74.5

Nov. 27 . . . . . . . . . . . .. Dec 6 . . . . . . . . . . .. 9 101 48 75.6

Nov 28 . . . . . . . . . . . .. Dec 6 . . . . . . . . . . .. 8 101 48 77.1

Nov 29 . . . . . . . . . . . .. Dec 7 . . . . . . . . . . .. 8 101 48 79.6

Nov 3O . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 8 101 48 79.3

Dec 1 . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 7 101 38 80.0

Dec 2 . . . . . . . . . . . . . Dec 11 . . . . . . . . . . .. 9 101 38 75.2

Dec 3 . . . . . . . . . . . .. Dec 15 . . . . . . . . . . .. 12 101 34 69.5

Dec 4 . . . . . . . . . . . .. Dec 2O . . . . . . . . . . .. 16 101 32 66.2

Dec 5 . . . . . . . . . . . . . Dec 26 . . . . . . . . . . . . 21 99 28 61.9

Dec 6 . . . . . . . . . . . . . Dec 27 . . . . . . . . . . . . 21 9O 28 61.0

Dec 7 . . . . . . . . . . . .. Jan 1, 1917 . . . . . . .. 25 90 28 60.3

Dec 8 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . 25 89 28 59.3

Dec 9 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . _ 24 92 28 58.9

Dec 10 . . . . . . . . . . . . . Jan 3 . . . . . . . . . . . . 24 92 28 59.9

Dec 1 1 . . . . . . . . . . . . . Jan 3 . . . . . . . . . . . . 23 92 28 59. 6

Dec 12 . . . . . . . . . . . .. Jan 4 . . . . . . . . . . .. 23 92 28 60.1

Dec 13 . . . . . . . . . . . . . Jan 4 . . . . . . . . . . . . 22 92 28 60.4

Dec 14 . . . . . . . . . . . .. Jan 4 . . . . . . . . . . .. 21 92 28 60.5

Dec 15 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 21 92 28 61.6

Dec 16 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 20 92 28 61.2

Dec 17 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 19 92 28 61.4

Dec 18 . . . . . . . . . . . .. Jan 6 . . . . . . . . . . .. 19 92 28 58.6

Dec 19 . . . . . . . . . . . .. Jan 7 . . . . . . . . . . .. 19 92 28 , 61.7

Dec . . . . . . . . . . . . .. Jan 7 . . . . . . . . . . .. 18 92 28 62.4

Dec 22 . . . . . . . . . . . . . Jan 7 . . . . . . . . . . . . 16 92 38 63.0

Dec 23 . . . . . . . . . . . . . Jan 8 . . . . . . . . . . .. 16 92 46 64.4 ~

Dec. 24 . . . . . . . . . . . .. Jan 8 . . . . . . . . . . .. 15 92 46 65.5

Dec. 25 . . . . . . . . . . . .. Jan 8 . . . . . . . . . . .. 14 92 46 65.9

Dec. 26 . . . . . . . . . . . .. Jan. 9 . . . . . . . . . . .. 14 93 46 66.2

, THE COWPEA WEEvIL. 21

Table 2.—Duration of the Egg Stage.—Continued.

Temperature
Laid Hatched Perod
Max. Min. Mean
1916
Dec. 27 . . . . . . _ . . . . .. Jan 9 . . . . . . . . . . . . 13 93 46 66.0

Dec. 2 . . . . . . . . . . . .. Jan 9 . . . . . . . . . . .. 12 93 46 63.6

Dec. 29 . . . . . . . . . . . .. Jan 10 . . . . . . . . . . .. 12 94 46 66.9

Dee. 30 . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 12 94 44 68.6

Deleéli; . . . . . . . . . . . .. Jan. 12 . . . . . . . . . . .. 12 94 44 67.8

Jan. . . . . . . . . . . . .. Jan 12 . . . . . . . . . . .. 11 94 44 69.0

Jan 2 . . . . . . . . . . . .. Jan 21 . . . . . . . . . . .. 19 94 30 56._4

Jan 3 . . . . . . . . . . . .. Jan 25 . . . . . . . . . . .. 22 94 30 55.0

Jan 4 . . . . . . . . . . . . . Jan 29 . . . . . . . . . . . . 25 94 30 55.2

Jan 5 . . . . . . . . . . . .. Jan 30 . . . . . . . . . . .. 25 100 30 54.6

Jan 6 . . . . . . . . . . . .. Jan 31 . . . . . . . . . . . .. 25 100 3O 55.4

Jan 7 . . . . . . . . . . . .. Feb 1 . . . . . . . . . . . . 25 100 30 56.4

Jan 8 . . . . . . . . . . . . . Feb 2 . . . . . . . . . . . . 25 100 25 55. 9

Jan 9 . . . . . . . . . . . . . Feb 8 . . . . . . . . . . . . 3O 100 25 53.9

Jan 10 . . . . . . . . . . . .. Feb 13 . . . . . . . . . . .. 34 100 25 52.7

Jan 11 . . . . . . . . . . . .. Feb 15 . . . . . . . . . . .. 35 100 25 51.4

Jan 12 . . . . . . . . . . . . . Feb 18 . . . . . . . . . . . . 37 100 25 53.2

Jan 20 . . . . . . . . . . . . _ Feb 18 . . . . . . . . . . . . 29 100 25 57.0

Jan 21 . . . . . . . . . . . .. Feb 18 . . . . . . . . . . .. 28 100 25 57.1

Jan 24 . . . . . . . . . . . . . . Feb 18 . . . . . . . . . . . . 25 100 25 57.2

Jan 25 . . . . . . . . . . . . . Feb 18 . . . . . . . . . . . . 24 100 25 57.6

Jan 26 . . . . . . . . . . . . . Feb 19 . . . . . . . . . . . . 24 100 25 61.0

Jan 27 . . . . . . . . . . . .. Feb 19 . . . . . . . . . . .. 23 100 25 61.0

Jan 28 . . . . . . . . . . . . . Feb 19 . . . . . . . . . . . . 22 100 25 58.0

Jan 29 . . . . . . . . . . . . . Feb 20 . . . . . . . . . . . . 22 100 25 08.4

Jan 30 . . . . . . . . . . . . . Feb 21 . . . . . . . . . . . . 22 103 ~25 58.5

Jan 31 . . . . . . . . . . . . . Feb 22 . . . . . . . . . . . . 22 103 25 57.9

Feb 2 . . . . . . . . . . . . . Feb 22 . . . . . . . . . . . . 20 103 30 56. 6

Feb 4 . . . . . . . . . . . . . Feb 2% . . . . . . . . . . . . 19 103 30 59.4

Feb 5 . . . . . . . . . . . . . Feb 23 . . . . . . . . . . . . 18 103 36 60.4

Feb 6 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 18 103 40 61.3

Feb 7 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 17 103 41 62.2

Feb 8 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 16 103 41 63.2

Feb 9 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 15 103 41 63.9

Feb 10 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 14 103 41 63.7

Feb 11 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 14 103 41 64.9

Feb 12 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 13 103 42 65.0

Feb 13 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 12 103 44 66.1

Feb 14 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 11 103 44 67.9

Feb 15 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 10 103 44 69.2

Feb 16 . . . . . . . . . . . . . . Feb 26' . . . . . . . . . . .  10 103 44 70.9

Feb 17 . . . . . . . . . . . . . Feb 26 . . . . . . . . . . . . 9 103 54 72.6

Feb 18 . . . . . . . . . . . . . Feb 26 . . . . . . . . . . . . 8 103 54 75.2

Feb 19 . . . . . . . . . . . .. Feb 27 . . . . . . . . . . .. 8 103 54 77.0

Feb 20 . . . . . . . . . . . . . Feb 28 . . . . . . . . . . . . 8 103 33 79.3

Feb 21 . . . . . . . . . . . .. Mar 6 . . . . . . . . . . . . 13 102 33 69.5

Feb 22 . . . . . . . . . . . . . Mar 9 . . . . . . . . . . . . 15 102 33 68.4

Feb 23 . . . . . . . . . . . .. Mar 11 . . . . . . . . . . .. 16 102 33 67.3

Feb 24 . . . . . . . . . . . .. Mar 13 . . . . . . . . . . . . 17 102 33 67.5

Feb 25 . . . . . . . . . . . .. Mar 14 . . . . . . . . . . .. 17 102 33 61.5

Duration- 0f Egg Stage.

Detailed observations have been made on the eggs of about 350
weevils covering a period of almost one and, one-half years. The
records were made in the laboratory- Where only natural temperature
conditions prevailed throughout the entire time. A thermograph was
used to record the existing temperatures during the period of observa-
tions. The results of the observations are shown in Table 2. For
each period the single highest temperature and the single lowest
temperature of the entire period are given. The mean temperature is
the average of the mean daily temperatures during the period.

The shortest period observed, 4 days, occurred frequently during the
warmer portions of 1916. In fact, every period during June, July,
and August, 191.6, was four days. The mean temperature necessary
for this short period ranges from 81 to 89.2 degrees F. During the

22 TEXAS AGRICULTURAL EXPERIMENT STATION.

period of three months when there was an unbroken record of four
days for the length of the egg stage, the mean temperature was 85.8
degrees F. In one instance a period of four days occurred with a mean
temperature for the period of only 80 degrees F.

The longest period of ‘the egg stage recorded was from January 12 to
February 19, 1917', a period of 37 days. During this period the lowest

temperature recorded was 25 degrees F. and the mean temperature for

the period was 53.9 degrees F.

The yearly variations in the duration of the egg stage are shown in
Table 3. The mean temperature evidently does not have positive in-
fluence upon the duration 0f the egg stage and in such cases continued
low temperature influence is evident.

Tab‘e 3.——Yearly Variation inYDuration of Egg Stage.

Period, Temperature,
Date Days - ean
November, 1915 . . . . . . . . . . . . . . . . . . .  6.5 l 75.6 ~

November, 1916 . . . . . . . . . . . . . . . . . . III 12.0 ; 70.0

December, 1915 . . . . . . . . . . . . . . . . . . . .l 17.4 I so. 1

December, 1916 . . . . . . . . . . . . . . . . . . . . 17.5 I 63.9

January, 1916 . . . . . . . . . . . . . . . . . . . . . .. 22.2 53.8

January, 1917 . . . . . . . . . . . . . . . . . . . . . . 25.2 56.5

February, 1916 . . . . . . . . . . . . . . . . . . . . . 19.4 60.4
14. 5 l 68.2

February, 1917 . . . . . . . . . . . . . . . . . . . . .

In Table 4 is given a summary of the duration of the egg stage
during the summer months and during the winter months. The aver-
age period during the warmest months was about 5 days and during the
coldest months the average period was about 15 days. The period
during the summer months is quite constant, but during the fall the
period increases slowly. During the winter the period is quite variable,
probably due to the variations in temperature at that season of the

' year in this locality.

Table 4.—Summary of Duration of the Egg Stage.

. Collections
Month Average Shortest Longest of Eggs
Period Period Period Observed
Days Days Days
June, 1916 . . . . . . . . . . . . . . . . . . . . . . . . 5 5 5 26

July, 1916 . . . . . . . . . . . . . . . . . . . . . . .. 5 5 5 26

August, 1916 . . . . . . . . . . . . . . . . . . . . . . 5 5 5 25

September, 1916 . . . . . . . . . . . . . . . . . . . 5 4 7 30

November, 1916 . . . . . . . . . . . . . . . . . . . 12.7 7 17 29

December, 1916 . . . . . . . . . . . . . . . . . . . 18.5 8 25 30

January, 1917. . . . . . . . . . . . . . . . . . . . . . 25.5 12 37 22

February, 1917 . . . . . . . . . . . . . . . . . . .. 14.8 8 19 22

There is quite a close relationship between the duration oi: the egg
stage and existing temperatures. This effect is shown in Table 5. The
low temperature at which the vitality of the eggs is destroyed was not

determined.

1 [Blank Page in Original Bulletin] ’

.3015 £95 miona QQPEA 315w?» swmfioO A: 35%

THE COWPEA W EEVIL. a 23

Table 5.—Efi'ect of Temperature on Duration of Egg Stage.

   

Avera e Daily
Month Perio , Temperature,
. . Days Degrees F.
June, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 86
5 87
August, 1916 . . . . . . . . . . . . ' 5 86

September, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 83.5

November, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.7 68.5

December, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18.5 y 64.6

January, 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25.5 60.3

February, 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14.8 62

Larva.

Descripti0nQ~The larva of B. qaadrimacalatus is a fleshy grub; its
body is fusiform. and yellowish-white in color; its head small and
brownish; its trophi dark brown. The length varies from 1 to 5 mm.
depending upon the inolt; the larva is strongly curved when in natural
position, the posterior end being considerably larger and tapering
abruptly to a blunt point on the anal extremity. Head small, wider
than long, light in color; antennae rudimentary; eye spots well defined.

Thoracic segments distinct, prothorax slightly larger; no bristles or

hairs present. Views of the larva are shown in Plate III.

Duration 0f Larval Stage.

Exact records were made on the duration of the larval stage of the
cowpea weevil for a period of almost one and one-half years. These
observations were made in the laboratory Where only natural tempera-
ture conditions prevailed throughout the entire time. A thermograph
was used to record the existing temperatures during the" period of
observation. The records made in‘ these observations are given in
Table 6. For each period are given its single highest temperature
and its single lowest temperature. The mean temperature given is the
average of the mean daily temperatures during the period. Normal
dry peas were the only food of the larvae.

Table 6.—Duration of Larval Stage.

_ Temperature
Hatched Pupated Period _
Max. Min. I .Mean
1915
Nov. . . . . . . . . . . . . . Nov 20 . . . . . . . . . . . . 18 84 57 73.3

Nov 2 . . . . . . . . . . . .. Nov. 20 . . . . . . . . . . .. 18 84 57 73.3 ’

Nov 2 . . . . . . . . . . . .. Nov. 21 . . . . . . . . . . .. 19 86 57 73.3

Nov 4 . . . . . . . . . . . .. Nov 22 . . . . . . . . . . .. 18 87 57 73.4

Nov 4 . . . . . . . . . . . .. Nov 24 . . . . . . . . . . .. 20 87 57 73.6

Nov 5 . . . . . . . . . . . .. Nov 24 . . . . . . . . . . .. 19 87 57 73.6

Nov 5 . . . . . . . . . . . . . Nov 25 . . . . . . . . . . . . 20 87 57 73.9 i

Nov 6 . . . . . . . . . . . . . Nov 26 . . . . . . . . . . .. 20 87 57 73.7

Nov 7 . . . . . . . . . . . .. Nov 26 . . . . . . . . . . .. 19 87 57 73.5

Nov 8 . . . . . . . . . . . .. Nov 27 . . . . . . . . . . .. 19 87 57 73.3

Nov . . . . . . . . . . . . . Nov 28 . . . . . . . . . . . . 19 87 57 73.7

Nov 10 . . . . . . . . . . . .. Nov 28 . . . . . . . . . . .. 18 87 57 73.4

Nov 11 . . . . . . . . . . . .. Nov 29 . . . . . . . . . . .. 18 87 57 73.3

Nov 12 . . . . . . . . . . . .. Dec. 1 . . . . . . . . . . .. 19 87 57 73.6

Nov 12 . . . . . . . . . . . .. Dec. 4 . . . . . . . . . . .. 22 87 57 74.2

Nov 16 . . . . . . . . . . . . .. Dec 3 . . . . . . . . . . .. 17 87 66 76.0

Nov 17 . . . . . . . . . . . .. Dec 4 . . . . . . . . . . .. 17 87 66 76.5

Nov 18 . . . . . . . . . . . .. Dec 3 . . . . . . . . . . .. 15 87 66 76.5

24 TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 6.—Duration of Larval stagger-Continued.

_ Temperature
Hatched Pupated Penod _
hdax Alum hdean
16 87 66 76.5
16 87 66 76.3
15 87 66 76.3
15 87 66 71.2
13 86 66 84.0
14 86 66 76.5
15 86 66 76.4
15 86 57 76.4
15 86 50 75.9
34 86 29 61.5
37 86 29 61.1
37 86 29 61.1
39 86 29 61.5
39 86 29 61.3
40 85 29 59.5
53 85 22 56.7
73 83 22 55.5
74 83 22 55.2
74 83 22 54.9
74 83 22 54.9
81 83 22 57.0
88 86 22 55.7
86 86 22 55.2
83 81 22 55.8
72 86 22 57.1
72 86 22 56.9
72 86 22 56.6
70 88 22 56.6
72 86 22 55.1
71 86 22 55.5
71 88 22 54.9
68 86 22 56.7
37 80 22 50.7
39 80 22 50.9
60 86 22 58.0
68 86 22 56.9
70 86 22 56.6
69 86 22 56.5
71 88 22 56.4
61 88 22 58.8
59 89 22 59.3
51 89 26 60.2
48 89 27 60.1
50 89 38 56.3
36 89 39 66.6
35 89 39 67.5
37 89 39 66.1
37 89 39 66.2
36 89 39 66.3
32 89 44 67.5
33 89 40 66.1
31 89 40 66.7
28 89 40 66.0
26 89 40 67.1
26 89 40 67.4
26 89 40 67.5
26 89 40 67.6
25 87 40 67.2
24 87 40 66.7
26 87 40 67.8
26 87 40 68.7
28 87 40 68.4
28 87 40 68.2
27 87 40 68.3
24 87 44 69.3
23 87 52 71.0
23 87 52 1 71.5
23 87 52 71.5
22 87 52 71.8
23 91 52 72.0
22 91 52 71.9
21 91 52 71.7
21 91 52 71.7
20 91 52 71.4
20 91 52 71.4
21 94 52 71.9
Aprfl16 . . . . . . . . . . . .. hday 6 . . . . . . . . . . .. 20 94 52 72.5

THE OQWPEA WVEEVIL.

Table 6.—Duration of Lz-lrval Stage.-—Continued.

25

Temperature
Hatched Pupated Period
hdax hdhn hdean
1916
Aprfl16 . . . . . . . . . . . .. hday 7 . . . . . . . . . . .. 21 96 52 73.0

AprU17 . . . . . . . . . . . .. hday 7 . . . . . . . . . . .. 20 96 52 73.6

Aprfl18 . . . . . . . . . . . .. hday 7 . . . . . . . . . . .. 19 96 52 74.0

Aprfl2O . . . . . . . . . . . . .. hday 8 . . . . . . . . . . .. 18 99 52 74.2

Apfil21 . . . . . . . . . . . .. hday 8 . . . . . . . . . . .. 17 99 52 74.3

Aprfl22. . . . . . . . . . . .. hday 9 . . . . . . . . . . .. 17 100 52 75.4

Apfll23 . . . . . . . . . . . .. hday 9 . . . . . . . . . . .. 16 100 52 75.5

Aprfl24 . . . . . . . . . . . .. hday 9 . . . . . . . . . . .. 15 100 52 75.6

Apfl125 . . . . . . . . . . . . .. hflay 10 . . . . . . . . . . .. 15 100 52 76.4
' 16 100 52 77.2
' 15 100 52 76.6

13 100 59 79.5
13 100 60 81.5
13 100 65 83.0
14 100 66 85.1
14 100 70 85.8
15 100 70 84.6
18 100 70 84.0
18 100 70 84.0
17 100 70 84.3
17 100 70 84.3
16 100 70 84.1
16 100 70 84.1
16 98 70 83.5
17 98 70 82.8
17 97 70 82.4
16 97 70 82.0
16 97 70 81.4
16 97 70 80.9
16 97 70 80.4
16 94 70 80.4
13 94 71 80.4
13 94 71 81.1
13 94 71 81.6
13 94 71 81.7
12 94 71 82.0
12 94 73 82.2
12 94 73 82.2
12 94 73 82.6
11 94 73 82.8
11 94 73 82.8
11 94 73 83.0
11 94 71 83.5
11 94 71 83.2
11 94 71 83.1
11 94 71 83.6
11 94 71 83.3
11 94 71 83.5
11 94 71 83.2
11 94 71 83.2
11* Q4 71 83.0
11 94 71 82.6
11 90 71 82.3
11 90 72 81.8
12 95 72 82.5
12 95 72 83.0
12 95 72 .83.0
12 95 72 83.1
12 95 72 83.3
12 95 72 83.9
12 95 72 84.1
12 95 74 84.5
12 95 75 85.0
12 95 75 85.3
12 95 75 85.5
12 95 75 85.7
11 95 75 85.9
11 95 75 85.6
10 95 75 85.7
10 95 75 85.6
10 95 75 85.3
10 97 75 85.2
10 99 76 85.3
10 99 76 85.8
10 99 76 86.2
10 99 76 86.7
10 99 76 87.2
10 99 76 87.2
10 99 77 87.3

26 TEXAS AGRICULTURAL EXPERIMENT STATION.
Table 6.—Duration of Larval Stage.
_ - Temperature

matched Pupated Penod _

Max Mm. Mean
1916 .

July 5 . . . . . . . . . . . .. July 15 . . . . . . . . . . .. 10 99 79 87.5

July 6 . . . . . . . . . . . .. July 16 . . . . . . . . . . .. 1O 99 79 87.6

July 7 . . . . . . . . . . . .. July 17 . . . . . . . . . . . . 10 99 79 87.8

July 8 . . . . . . . . . . . . . July 18 . . . . . . . . . . . . 10 99 78 87.8

July 9 . . . . . . . . . . . .. July 19 . . . . . . . . . . .. 10 99 78 87.6

July 1O . . . . . . . . . . . .. July 0 . . . . . . . . . . .. 10 99 78 87.4

July 11 . . . . . . . . . . . .. July 20 . . . . . . . . . . . . 9 99 78 87.2

July 12 . . . . . . . . . . . .. July 22 . . . . . . . . . . . . 10 99 78 87.3

July 14 . . . . . . . . . . . .. July 23 . . . . . . . . . . . . 9 99 78 88.0

July 15 . . . . . . . . . . . . . July 24 . . . . . . . . . . .. 9 99 78 87.0

July l6 . . . . . . . . . . . .. July 27 . . . . . . . . . . .. 11 99 78 88.0

July 17 . . . . . . . . . . . .. July 27 . . . . . . . . . . . . 10 99 78 88.1

July 18 . . . . . . . . . . . .. July 28 . . . . . . . . . . .. 10 99 78 87.7

July 19.. July 28 . . . . . . . . . . .. 9 99 78 87.6

July 2O . . . . . . . . . . . .. July 29 . . . . . . . . . . .. 9 99 78 87.7

July 21 . . . . . . . . . . . .. July 3O . . . . . . . . . . .. 9 99 78 87.7

July 22 . . . . . . . . . . . . .. July 31 . . . . . . . . . . .. 9 99 78 87.0

July 23 . . . . . . . . . . . .. Aug. 1 . . . . . . . . . . .. 9 99 78 86.6

July 24 . . . . . . . . . . . .. Aug. 2 . . . . . . . . . . .. 9 99 78 87.1

July 25 . . . . . . . . . . . .. Aug. 3 . . . . . . . . . . .. 9 99 78 86.8

July 26 . . . . . . . . . . . .. Aug. 4 . . . . . . . . . . .. 9 99 78 86.6

July 27 . . . . . . . . . . . . .. Aug. 5 . . . . . . . . . . .. 9 99 78 86.8

July 28 . . . . . . . . . . . .. Aug. 6 . . . . . . . . . . .. 9 97 78 87.3

July 29 . . . . . . . . . . . .. Aug. 8 . . . . . . . . . . .. 1O 97 78 86.6

July 30 . . . . . . . . . . . . . Aug. 9 . . . . . . . . . . . . 10 97 78 86.5

July 31 . . . . . . . . . . . .. Aug 10 . . . . . . . . . . . . 10 97 78 86.6

Aug. 1 . . . . . . . . . . . .. Aug 11 . . . . . . . . . . .. 10 97 79 6.2

Aug. 2 . . . . . . . . . . . . . Aug 12 . . . . . . . . . . . . 10 97 79 5.9

Aug. 3 . . . . . . . . . . . . . Aug 13 . . . . . . . . . . . . 10 96 79 85.8

Aug. 4. . . . . . . . . . . . . Aug 14 . . . . . . . . . . . . 10 96 79 85.7

Aug. 5 . . . . . . . . . . . . .. Aug 16 . . . . . . . . . . . . 11 496 79 85.7

Aug. 6 . . . . . . . . . . . .. Aug 17 . . . . . . . . . . .. 11 96 75 85.5

Aug. 7 . . . . . . . . . . . . . Aug 17 . . . . . . . . . . .. 10 96 75 86.0

Aug. 8 . . . . . . . . . . . . . Aug 18 . . . . . . . . . . . . . 10 96 75 85.8

Aug 9 . . . . . . . . . . . . . Aug 19 . . . . . . . . . . . . 10 96 75 85.8

Aug 10 . . . . . . . . . . . .. Aug 20 . . . . . . . . . . .. 10 96 75 86.0

Aug 11 . . . . . . . . . . . .. Aug 20 . . . . . . . . . . .. 9 96 75 86.2

Aug 12 . . . . . . . . . . . . . Aug. 21 . . . . . . . . . . . . 9 100 75 86.4

Aug 13 . . . . . . . . . . . .. Aug 22 . . . . . . . . . . .. 9 100 75 87.0

Aug 14 . . . . . . . . . . . . . Aug. 25 . . . . . . . . . . . . 11 100 73 86.9

Aug 15.- . . . . . . . . . . . . Aug. 26 . . . . . . . . . . . . 11 100 70 86.3

Aug 16 . . . . . . . . . . . . . Aug. 28 . . . . . . . . . . . . 12 100 70 85.8

Aug 17 . . . . . . . . . . . .. Aug. 29 . . . . . . . . . . .. 12 100 70 85.7

Aug 18 . . . . . . . . . . . . . Aug. 30 . . . . . . . . . . . . 12 100 7O 86.0

Aug 19 . . . . . . . . . . . .. Aug 31 . . . . . . . . . . .. 12 100 70 86.0

Aug. 20 . . . . . . . . . . . . . Sept 1 . . . . . . . . . . . . 12 100 7O 86.0

Aug. 21 . . . . . . . . . . . . . Sept 2 . . . . . . . . . . . . 12 97 70 85.9

Aug 22 . . . . . . . . . . . .. Sept 2 . . . . . . . . . . .. 11 97 70 85.4

Aug. 23 . . . . . . . . . . . . . Sept 3 . . . . . . . . . . . . 11 97 70 85.4

Aug. 25 . . . . . . . . . . . . . Sept 5 . . . . . . . . . . . . 11 97 70 85.7

Aug 26 . . . . . . . . . . . .. Sept 7 . . . . . . . . . . .. 12 97 75 86.4

Aug. 27 . . . . . . . . . . . . . Sept 8 . . . . . . . . . . . . 12 101 77 86.9

Aug. 28 . . . . . . . . . . . . . Sept. 10 . . . . . . . . . . . . 13 101 77 87.7

Aug. 29 . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . 13 101 77 87.7

Aug. 30 . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . 12 101 78 88.0

Sept. 1 . . . . . . . . . . . . . Sept. 12 . . . . . . . . . . . . 11 101 80 80.3

Sept. 2 . . . . . . . . . . . . . Sept. 13 . . . . . . . . . . . . 11 101 79 88.5

Sept. 3 . . . . . . . . . . . . . Sept. 14 . . . . . . . . . . . . 11 101 78 88.5

Sept. 4 . . . . . . . . . . . . . Sept. 14 . . . . . . . . . . . . 1O 101 78 88.6

Sept. 4.‘ . . . . . . . . . . . . Sept. 16 . . . . . . . . . . . . 12 101 70 88 4

Sept. 6 . . . . . . . . . . . . . Sept. 17 . . . . . . . . . . . . 11 101 70 86.7

Sept. 7, . . . . . . . . . . . . . Sept. 18 . . . . . . . . . . . . 11 101 67 85.7

Sept. 8 . . . . . . . . . . . . . Sept. 19 . . . . . . . . . . . . 11 99 67 85.2

Sept. 9 . . . . . . . . . . . . . Sept. 2O . . . . . . . . . . . . 11 99 67 84.1

Sept. 10 . . . . . . . . . . . . . Sept. 23 . . . . . . . . . . . . 13 99 67 83.0

Sept. 11 . . . . . . . . . . . . . Sept. 24 . . . . . . . . . . . . 13 99 67 82.4

Sept. 12 . . . . . . . . . . . . . Sept. 25 . . . . . . . . . . . . 13 99 67 81.8

Sept. 12 . . . . . . . . . . . . . Sept. 27 . . . . . . . . . . . . 15 105 67 81 . 5

Sept. 14 . . . . . . . . . . . . . Sept. 28 . . . . . . . . . . . . 14 105 67 81.2

Sept. 15 . . . . . . . . . . . . . Sept 3O . . . . . . . . . . . . 15 105 57 80.7

Sept. 16 . . . . . . . . . . . .. Oct 2 . . . . . . . . . . .. 16 105 57 78.7

Sept. 18 . . . . . . . . . . . . . Oct 3 . . . . . . . . . . . . 15 105 57 78.6

Sept. 19 . . . . . . . . . . . . . Oct 4 . . . . . . . . . . . . 15 105 57 78:2

Sept. 2O . . . . . . . . . . . . . Oct 5 . . . . . . . . . . . . 15 105 57 78.2

Sept. 21 . . . . . . . . . . . . . Oct 6 . . . . . . . . . . . . 15 105 57 78.0

Sept. 22 . . . . . . . . . . . . . Oct 7 . . . . . . . . . . . . 15 105 57 77.8

Sept. 22 . . . . . . . . . . . . . Oct 8 . . . . . . . . . . . . 16 105 57 77.6

Sept. 23 . . . . . . . . . . . . . Oct 8 . . . . . . . . . . . . 15 105 57 77.6

Sept 24 . . . . . . . . . . . . . . Oct 9 . . . . . . . . . . . . 15 105 57 77.6

THE COWPEA WYEEVIL.

Table 6.—Duration of Larval Stage.—Continued.

2'7

_ Temperature
Hatched Pupated Penod
Max Min. Mean
1916 .
Sept. 26 . . . . . . . . . . . . . Oct. 11 . . . . . . . . . . . . 15 105 57 77. 6

Sept. 27 . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 15 95 57 77. 5

Sept. 28 . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 15 94 57 76. 8

Sept. 29 . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 14 94 57 76.1

Oct. 1 . . . . . . . . . . . . . Oct. 14 . . . . . . . . . . . . 1'3 94 64 77. 5

Oct. 2 . . . . . . . . . . . . . Oct. 15 . . . . . . . . . . . . 13 94 66 78. 6

Oct. 3 . . . . . . . . . . . . . Oct. 16 . . . . . . . . . . . . 13 94 65 79. O

Oct. 4 . . . . . . . . . . . . . Oct. 17 . . . . . . . . . . . . 13 94 65 78.9

Oct. 5 . . . . . . . . . . . . . Oct. 18 . . . . . . . . . . . . 13 94 61 78.6

Oct. 6 . . . . . . . . . . . .. Oct. 21 . . . . . . . . . . . . 15 94 61 76.1

Oct. 6 . . . . . . . . . . . . . Oct 22 . . . . . . . . . . . . 16 94 41 75.0

Oct. 7 . . . . . . . . . . . . . Oct 23 . . . . . . . . . . . . 16 94 41 74. 2

Oct. 8 . . . . . . . . . . . . . Oct. 25 . . . . . . . . . . . . 17 95 41 74.4

Oct. 8 . . . . . . . . . . . . . Oct. 28 . . . . . . . . . . . . 20 95 41 73. 6

Oct. 9 . . . . . . . . . . . . . Oct 29 . . . . . . . . . . . . 20 95 41 73. 1

Oct. 10 . . . . . . . . . . . . . Oct 30 . . . . . . . . . . . . 20 95 41 72. 5

Oct. 11 . . . . . . . . . . . . . Oct 31 . . . . . . . . . . . . 20 95 41 72 6

Oct. 12 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . . . 20 95 41 73. 0

Oct. 13 . . . . . . . . . . . . . Nov 4 . . . . . . . . . . . . 22 95 41 72.9

Oct. 14 . . . . . . . . . . . . . Nov 5 . . . . . . . . . . . . 22 95 41 72.5»

Oct. 15.. . . . . . . . .. Nov 5 . . . . . . . . . . . . 21 95 41 72.1

Oct. 16 . . . . . . . . . . . . . Nov 6 . . . . . . . . . . . . 21 95 41 72.1

Oct. 18 . . . . . . . . . . . . . Nov 16 . . . . . . . . . . . . 29 95 33 70.1

Oct. 22 . . . . . . . . . . . .. Nov 18 . . . . . . . . . . . . 27 95 33 70.0-

Oct. 23 . . . . . . . . . . . .. Nov 20 . . . . . . . . . . . . 28 95 33 70.3

Oct. 25 . . . . . . . . . . . . . Nov 24 . . . . . . . . . . . . 30 94 33 69.7

Oct. 27 . . . . . . . . . . . .. Nov 25 . . . . . . . . . . . . 29 94 33 69.2‘

Oct. 28 . . . . . . . . . . . . . Nov 25 . . . . . . . . . . . . 28 94 33 69.5-

Oct. 28 . . . . . . . . . . . . . Nov 26 . . . . . . . . . . . . 29 94 33 69.4

Oct. 29 . . . . . . . . . . . . . Nov. 26 . . . . . . . . . . . . 28 94 33 69.3»

Oct. 29 . . . . . . . . . . . . . Nov. 27 . . . . . . . . . . . . 29 98 33 69. 2

Oct. 30 . . . . . . . . . . . . . Nov 28 . . . . . . . . . . . . 29 98 33 68.5

Oct. 30 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 29 98 33 68.5

Nov 1 . . . . . . . . . . . . . Nov. 29 . . . . . . . . . . . . 28 98 33 68. 1

Nov 2 . . . . . . . . . . . . . Nov. 30 . . . . . . . . . . . . 28 98 33 68.0

Nov 2 . . . . . . . . . . . . . Dec 1 . . . . . . . . . . . . 29 98 33 68.3

Nov 2 . . . . . . . . . . . . . Dec 3 . . . . . . . . . . . . 31 98 33 68.7

Nov 4 . . . . . . . . . . . . . Dec 4 . . . . . . . . . . . . 30 98 33 68.4

Nov 4 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 31 101 33 68. 9'

Nov 5 . . . . . . . . . . . . . . Dec 6 . . . . . . . . . . . . 31 101 33 69. 5~

Nov 7 . . . . . . . . . . . . . Dec 7 . . . . . . . . . . . . 3O 101 33 69. 5

Nov 7 . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 31 101 33 69.91

Nov 8 . . . . . . . . . . . . . Dec 11 . . . . . . . . . . .. 33 101 ' 33 69.1

Nov 11 . . . . . . . . . . . .. Dec 12 . . . . . . . . . . . . 31 101 33 68. 5-

Nov 12 . . . . . . . . . . . . . Dec 17 . . . . . . . . . . . . 35 101 32 66. 8-

Nov. 16 . . . . . . . . . . . . . Dec 24 . . . . . . . . . . . . 38 1E1 28 65.5

Nov. 19 . . . . . . . . . . . .. Dec. 25 . . . . . . . . . . . . 36 101 28 62.8

Nov. 20 . . . . . . . . . . . .. Jan 2 . . . . . . . . . . . . 43 101 28 65.7

<Nov. 21 . . . . . . . . . . . .. Jan 2 . . . . . . . . . . . . 42 101 28 65.4

Nov. 25 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . 38 101 28 64.61

Nov. 26 . . . . . . . . . . . .. Jan 3 . . . . . . . . . . . . 38 101 28 65. 0"

Nov. 27 . . . . . . . . . . . . . Jan 4 . . . . . . . . . . . . 38 101 28 65.2

Nov. 28 . . . . . . . . . . . .. Jan 7 . . . . . . . . . . .. 40 101 28 65.4

Nov. 29 . . . . . . . . . . . . . Jan 8 . . . . . . . . . . . . 40 101 28 65.2

Nov. 29 . . . . . . . . . . . . .. Jan 9 . . . . . . . . . . . . 41 101 28 65.3

Nov. 30 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . . . 36 101 28 64. 7

Nov 30 . . . . . . . . . . . . . Jan 6 . . . . . . . . . . . . 37 101 28 64.7

Dec 1 . . . . . . . . . . . . . Jan 6 . . . . . . . . . . . . 36 101 - 28 64.7

Dec 1 . . . . . . . . . . . . . Jan. 7 . . . . . . . . . . . . 37 101 28 64.7

Dec 2 . . . . . . . . . . . . . Jan. 10 . . . . . . . . . . . . 39 101 28 63.5

Dec 3 . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . . . 39 101 28 65.0

Dec 4 . . . . . . . . . . . . . Jan. 26 . . . . . . . . . . . . 53 101 28 60.91

Dec 5 . . . . . . . . . . . . . Jan. 27 . . . . . . . . . . . . 53 99 28 60. 5A

Dec 5 . . . . . . . . . . . . . Jan. 27 . . . . . . . . . . . . 53 99 28 60. 5

Dec 6 . . . . . . . . . . . .. Jan. 28 . . . . . . . . . . . . 53 94 28 61 . 0

Dec 6 . . . . . . . . . . . . . Jan. 29 . . . . . . . . . . . . 54 94 28 61.0

Dec 6 . . . . . . . . . . . . .. Jan. 29 . . . . . . . . . . . . 54 94 _ 28 61.0

Dec 6 . . . . . . . . . . . . . Jan. 30 . . . . . . . . . . . . 55 100 28 61. 1

Dec 6 . . . . . . . . . . . . . Jan. 30 . . . . . . . . . . . . 55 100 28 61. 1

Dec 7 . . . . . . . . . . . .. Jan. 31 . . . . . . . . . . . . 55 100 28 61 . 1

Dec 8 . . . . . . . . . . . . . Feb. 6 . . . . . . . . . . . . 60 100 25 59.2

Dec 11 . . . . . . . . . . . . . Feb. 13 . . . . . . . . . . . . 64 100' 28 58. 6

Dec 15 . . . . . . . . . . . .. Feb .17 . . . . . . . . . . .. 64 100 28 58.4

Dec 20 . . . . . . . . . . . . . Feb. 20 . . . . . . . . . . . . 62 100 25 58.7

Dec 26 . . . . . . . . . . . . . Feb 21 . . . . . . . . . . . . 57 100 25 59. 3

Dec 27 . . . . . . . . . . . . . Feb 24 . . . . . . . . . . . . 59 103 25 60. 1
1917
Jan. 1 . . . . . . . . . . . . . Feb 25 . . . . . . . . . . . . 55 103 25 60.1

28 TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 6. Duration of Larval Stage-Continued.

_ Temperature
Hatched Pupated Period
hdax. hdin. hdean
54 103 25 60.1
55 103 25 60.4
54 103 25 60.0
54 103 25 60.0
53 103 25 59.9
54 103 25 60.0
55 103 25 60.9
54 103 25 60.5
54 103 25 60.5
54 103 25 60.5
53 103 25 60.6
53 103 25 60.9
53 103 25 60.9
54 103 25 61.0
53 103 25 60.9
53 103 25 60.9
53 103 25 60.9
52 103 25 60.7
52 103 25 60.7
53 103 25 60.5
52 103 25 60.2
52 103 25 59.6
53 103 25 59.1
55 103 25 59.3
46 103 25 61.7
45 103 25 62.7
42 103 25 63.4
43 103 25 64.0
43 103 25 63.3
42 103 25 63.2
42 103 30 63.3
36 103 30 65.8
35 103 35 67.0
32 103 35 68.2
30 103 35 69.3
30 103 33 69.3
32 103 33 68.7
31 103 33 69.0
30 103 33 69.3
30 103 33 69.1
29 103 33 69.3
29 103 33 69.3
29 103 35 69.1
28 103 35 69.1
28 102 33 69.1
28 102 33 69.1
29 102 33 69.2
33 102 33 69.9
30 102 33 71.7
30 102 33 71.7
28 102 33 71.9
28 102 33 71.9
29 102 33 71.7
31 102 33 71.9
32 102 33 71.7
29 102 33 70.9
28 102 33 68.7
28 102 33 68.7
29 102 33 68.0
31 102 33 69.2
. . 31 100 33 69.0
Feb. 28 . . . . . . . . . . . .. h4ar.30 . . . . . . . . . . .. 30 99 33 68.7

The shortest larval stage observed, 9 days, occurred frequently during
July, 1916. The mean temperature during these periods ranged from
86.6 to 88.2 degrees F. The longest larval period of 88 days was from
December 11, 1915, to March 8, 1916. During this period the mean
temperature was 55.5 degrees F.; the lowest temperature during the
period was 22 degrees F. and the highest temperature recorded was
86 degrees F. '

The yearly variation in the duration of the larval stage is shown in
Table '7. The mean temperature of the period shows a direct effect

THE OoWPEA WEEvIL. I 29

upon the length of the stage. A slight decrease in the mean tempera-
ture results in a much increased length of the larval stage.

Table 7.—Yearly Variation in Duration of Larval Stage.

Period, _ Temperature,
Date Days Mean
November, 1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17.5 75.0

November, 1916 . . . . . . . . . . . . . . . . . . . . .._ . .~. . . . . . . . . . .. 35.5 65.7

December, 1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.7 55.8

December, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53.2 60.4

January, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68.2 57.3

January, 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53.2 61.4

February, 1916 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.8 63.7

February. 1917 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30.3 67.3

In Table 8 is given a summary of the duration of the larval stage
during representative summer months and winter months. The aver-
age period during the warmest months was 11.5 days and during the
coldest months the average period was 45.9 days. The period during
the warmer months Was quite constant, but during the colder, months
it was variable, no doubt, because of local variations in climate.

Table;8.—Summary of Duration of Larval Stage.

 

Number
Month Average Shortest Longest Collections
_ Period Period Period Observed
I
June . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 10 | 12 29

July . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. 6 9 11 3O

August . . . . . . . . . . . . . . . . . . . . . . . . . . 11 . 6 9 13 29

September . . . . . . . . . . . . . . . . . . . . . . . . 13.5 10 16 28

November . . . . . . . . . . . . . . . . . . . . . . 25. 6 13 13 52

December . . . . . . . . . . . . . . . . . . . . 61.2 36 88 29

January . . . . . . . . . . . . . . . . . . . . . . _ . .- 60.0 42 72 47

February . . . . . . . . . . . . . . . . . . . . . . . . . 1 36. s 2s 51 40

The relationship of temperature to the duration of the larval stage
is not so noticeable as was the case with the egg stage. The results
of the observations made are given in Table 9. Neither the low
temperature at which growth ceased n.or the vital low telnperature were
determined. a

Table 9.——Effect of Temperature on Length of Larval Stage.

Average I Mean Daily
Month Period Temperature
Days Degrees
June . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 . 2 86 . 0

July . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. 6 87. 0

August . . . . . . . . . . . . . . . . . . . . . . .. 11.6 89.0

September . . . . . . . . . . . . . . . . . . . . . 13 . 5 83. 5

November . . . . . . . . . . . . . . . . . . . . . 25.6 71 . 9

December . . . . . . . . . . . . . . . . . . . . . 61 . 2 62. 2

January . . . . . . . . . . . . . . . . . . . . . .. 60.0 58.6

February . . . . . . . . . . . . . . . . . . . . . . 36 . 8 58. 5

30 TEXAS AGRICULTURAL EXPERIMENT STATION.

Papa.

Descriptionr-Pupa stout and compact, White in color, free from
bristles or hairs.

Ventral view: Outline oval, tapering to a blunt point distally,
broadly rounded anteriorly. Head distinct, bent closely upon thorax;
mouth parts immediately between coxae of first pair of legs; mandibles
distinct; palpi free, segments distinct, reaching second pair of legs.
Eyes not prominent; antennae strongly curved, passing behind first
and second pairs of le-gs, lying flat upon the elytra, segmentation quite
distinct, almost three-fourths as long as elytra; longitudinal ridges of
elytra very distinct. First and second pairs of legs about equal in
length, folded horizontally over elytra; tarsi parallel with body, seg-
mentation distinct; last pair of legs covered by Wing's, except tarsi,
which reach almost to the base of the last abdominal segment.

Lateral view: Head defiexed, prothorax depressed anteriorly, spir-
acle-s inconspicuous; first and second pairs of legs cover basal portion
of elytra beneath the antennae; antennae curved ventrally behind the
legs to about last one-fourth of elytra; win.gs prominent, curved ventrally
behind second pair of legs and cover all but itarsi of last pair of legs;
abdominal segments distinct, spiracles inconspicuous.

Dorsal view: Head concealed by prothorax; thoracic segments dis-
tinct, prothorax more or less triangular in outline, much wider pos-

teriorly, terminating in sharp points above base of wings, median line.

conspicuous, abdominal segments nearly equal in size. Views of the
pupa are shown in Plate lII.

Table 10.—Measurements of Pupa.
(Measured with steel caliper.)

Length Width
(greatest) (greatest)
1 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.0 mm. 2.0 mm.

2 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.5 mm. 2.2 mm.

3 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.0 mm. 2.0 mm.

4 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.5 mm. 2.2 mm.

5 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.5 mm. 1.7 mm

6 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.0 mm. 2.0 mm

7 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.5 mm. 1.7 mm

8 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.7 mm. 1.7 mm

9 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.5 mm. 1.7 mm

10 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.0 mm. 2.0 mm

11 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.5 mm. 1.7 mm

12 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.2 mm. 2.2 mm

13 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.5 mm. 2,2 mm

14 . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.2 mm. 1.7 mm

Average . . . . . . . . . . . . . . . . . .. 3.9 mm. 1.9 mm.

Duration 0f Papal Stage.

Records on the duration of the pupal stage of the cowpea weevil
were made over a period of almost one and one-half years. This work

‘was conducted in the laboratory where only natural temperatures pre-

vailed. The existing temperatures of the period were recorded by a
thermograph. The results of these observations are given in Table 11.
For each period the single highest temperature andthe single lowest
temperature are given. The mean temperature given is an average of

the mean daily temperatures during the pcrlod.

THE COWPEA W EEVIL.

Normal dry peas were

 

used.
Table llr-Durnfon o’ Pupal Stage.
_ Temperature
Pupated Emerged Per 0d _
Max. ~ Mm. Mean
1915
Nov. 1 . . . . . . . . . . . . . Nov. 5 . . . . . . . . . . . . 4 - - 82 66 75. 2

Nov. 1 . . . . . . . . . . . . . Nov. 9 . . . . . . . . . . . . 8 82 66 75.6

Nov 2 . . . . . . . . . . . .. Nov. 9 . . . . . . . . . . ..- 7 83 66 75.5

Nov 3 . . . . . . . . . . . .. Nov. 10 . . . . . . . . . . .. 7 82 66 75.8

Nov 4 . . . . . . . . . . . .. Nov. 9 . . . . . . . . . . .. 5 82 74 75.5

Nov 5 . . . . . . . . . . . . . Nov. . . . . . . . . . . . . 4 83 74 76.1

Nov 6 . . . . . . . . . . . .. Nov. 11 . . . . . . . . . . .. 5 83 76~ 77.1

Nov 7 . . . . . . . . . . . . . Nov. 15 . . . . . . . . . . . . 8 83 57 72. 5

Nov 8 . . . . . . . . . . . . . Nov. 15 . . . . . . . . . . . . 7 83 57 72. 7

Nov 9 . . . . . . . . . . . .. Nov, 17 . . . . . . . . . . .. 8 84 57 70.2

Nov 10 . . . . . . . . . . . . . Nov. 19 . . . . . . . . . . . . 9 84 57 70. 6

Nov 11 . . . . . . . . . . . .. Nov. 20 . . . . . . . . . . .. 9 86 57 70.5

Nov 12 . . . . . . . . . . . .. Nov. 21 . . . . . . . . . . .. 9 87 57 ' 71.1

Nov 13 . . . . . . . . . . . . . Nov. 22 . . . . . . . . . . . . 9 87 57 72. 1

Nov 16 . . . . . . . . . . . . . Nov. 22 . . . . . . . . . . . . 6 87 57 75.2

Nov 17 . . . . . . . . . . . . . Nov. 23 . . . . . . . . . . . . 6 87 69 73.8

Nov 18 . . . . . . . . . . . . . Nov. 24 . . . . . . . . . . . . 6 87 66 76.5

Nov 20 . . . . . . . . . . . . . Nov. 24 . . . . . . . . . . . . 4 87 66 76. 3

Nov 20 . . . . . . . . . . . . . Nov. 24 . . . . . . . . . . . . 4 87 66 76.3

Nov 20 . . . . . . . . . . . . . Nov. 23 . . . . . . . . . . . . 3 87 69 77.3

Nov. 22 . . . . . . . . . . . .. Nov. 26 . . . . . . . . . . .. 4 81 66 75.5

Nov. 24 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 4 82 66 76.0

Nov. 24 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 4 82 72 76. 0

Nov. 25 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 3 82 72 77.0

Nov. 26 . . . . . . . . . . . . . Nov. 29 . . . . . . . . . . . . 3 82 73 77. 0

Nov. 26 . . . . . . . . . . . . . Nov. 30 . . . . . . . . . . . . 4 82 72 76. 5

Nov. 27 . . . . . . . . . . . .. Dec 3 . . . . . . . . . . .. 6 86 70 77.0

Nov. 28 . . . . . . . . . . . . . Dec 4 . . . . . . . . . . . . 6 86 7O 76.8

Nov. 28 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 7 86 67 76.8

Nov 29 . . . . . . . . . . . .. Dec 5 . . . . . . . . . . .. 6 86 67 76.5

Dec 1 . . . . . . . . . . . . . Dec 7 . . . . . . . . . . . . 6 86 68 77.5

Dec 3 . . . . . . . . . . . . . Dec. 7 . . . . . . . . . . . . 4 85 67 77.2

Dec 3 . . . . . . . . . . . .. Dec. 11 . . . . . . . . . . .. 8 85 50 75.0

Dec 4 . . . . . . . . . . . . . Dec. 30 . . . . . . . . . . . . 26 85 29 58. 1

Dec 5 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . .. 28 85 29 57.4

Dec 5 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . 28 85 29 57.4

Dec 5 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . 28 85 29 57.4

Dec 7 . . . . . . . . . . . .. Jan 3 . . . . . . . . . . .. 27 83 29 56.9

Dec 9 . . . . . . . . . . . . . Jan 2 . . . . . . . . . . . . 24 83 29 54.2

Dec 10 . . . . . . . . . . . .. Jan 10 . . . . . . . . . . .. 31 83 29 55.6

Dec 11 . . . . . . . . . . . .. Jan 10 . . . . . . . . . . .. 30 76 29 55.2

Dec. 31 . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . .. 11 76 45 61.7
1916
Jan. 4 . . . . . . . . . . . .. Jan. 28 . . . . . . . . . . .. 24 79 22 55.1

Jan. 5 . . . . . . . . . . . .. Feb. 27 . . . . . . . . . . .. 53 8O 22 56.0

Jan. 7 . . . . . . . . . . . .. Feb. 22 . . . . . . . . . . .. 46 8O 22 53.6

Jan 8 . . . . . . . . . . . .. Feb. 22 . . . . . . . . . . .. 45 80 22 54.5

Jan 12 . . . . . . . . . . . .. Feb. 23 . . . . . . . . . . .. 42 80 22 53.1

Jan 26 . . . . . . . . . . . . . Mar 3 . . . . . . . . . . . . 37 81 26 54.7

Feb 16 . . . . . . . . . . . .. Mar 12 . . . . . . . . . . .. 25 86 39 61.0

Feb 18 . . . . . . . . . . . .. Mar 12 . . . . . . . . . . .. 23 86 39 62.0

Feb 19 . . . . . . . . . . . . . Mar 20 . . . . . . . . . . .. 30 86 39 62.3

Feb 2O . . . . . . . . . . . . . Mar 2O . . . . . . . . . . .. 29 86 39 62.8 .

Mar 1 . . . . . . . . . . . .. Mar 0 . . . . . . . . . . .. 19 86 39 63.6 _

Mar 5 . . . . . . . . . . . . . Apr; 6 . . . . . . . . . . . . 32 89 44 67.2

Mar 7 . . . . . . . . . . . . . Aprll 6 . . . . . . . . . . . . 3O 89 44 67. 6

‘Mar s . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 12 s6 44 65.0

Mar. 16 . . . . . . . . . . . . . Aprll 6 . . . . . . . . . . . . 21 89 4O 67.9

Mar. 17 . . . . . . . . . . . . . Mar. 25 . . . . . . . . . . . . 8 89 53 71.6

Mar. 17 . . . . . . . . . . . . . Mar. 25 . . . . . . . . . . . . 8 89 53 71 . 6

Mar. 18 . . . . . . . . . . . . . Mar. 23 . . . . . . . . . . . . 5 89 61 74. 0

Mar. 19 . . . . . . . . . . . . . Mar. 23 . . . . . . . . . . . . 4 89 63 75. 5

Mar. 19 . . . . . . . . . . . . . Mar. 28 . . . . . . . . . . . . 9 89 48 71.1

Mar. 19 . . . . . . . . . . . . . Mar. 28 . . . . . . . . . . . . 9 89 48 71 . 1

FMar. 19 . . . . . . . . . . . . . Mar. 29 . . . . . . . . . . . . 10 89 48 70.1

iMar. 19 . . . . . . . . . . . . . April 11 . . . . . . . . . . . . 23 89 40 66. 8

EMar. 20 . . . . . . . . . . . . . Mar. 24 . . . . . . . . . . . . 4 89 60 75. 7

.,Mar. 20 . . . . . . . . . . . . . Mar. 24 . . . . . . . . . . . . 4 89 60 75. 7

iMar. 2O . . . . . . . . . . . . . Mar. 25 . . . . . . . . . . . . 5 89 6O 74.8

EMar. 21 . . . . . . . . . . . . . Mar. 24 . . . . . . . . . . . . 3 89 6O 76.6

EMar. 21 . . . . . . . . . . . . . Mar. 25 . . . . . . . . . . . . 4 89 60 75.0

fMar. 21 . . . . . . . . . . . . . Mar. 31 . . . . . . . . . . . . 10 89 48 69. 8

gMar. 22 . . . . . . . . . . . . . Mar 31 . . . . . . . . . . . . 9 86 48 69.0

~Mar. 22 . . . . . . . . . . . . . April 6 . . . . . . . . . . . . 15 86 48 68.0

gMar. 24 . . . . . . . . . . . . . Aprll 2. . . . . . . . . . . . 9 86 48 67.7

32- TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 11.-—Duration of Pupal Stage.—Continued.

_ Temperature
Pupated Emerged Period
Max Min. Mean
1916 _
Mar. 25 . . . . . . . . . . . . . April 6 . . . . . . . . . . . . 12 86 48 6615

Mar. 30 . . . . . . . . . . . . . April 13 . . . . . . . . . . . . 14 83 4O 64.7

Mar. 31 . . . . . . . . . . . .. April 16 . . . . . . . . . . .. 16 83 40 66,3

April 6 . . . . . . . . . . . . . April 17 . . . . . . . . . . . . 11 85 40 65,6

April 7 . . . . . . . . . . . . . April 16 . . . . . . . . . . . . 9 83 4O 65_5

April 8 . . . . . . . . . . . . . April 17 . . . . . . . . . . . . 9 85 40 5515

April 8 . . . . . . . . . . . . . April 19 . . . . . . . . . . . . 11 87 40. 66_7

April 1O . . . . . . . . . . . . . April 20 . . . . . . . . . . . . 10 87 53 70_ 5

April 11 . . . . . . . . . . . . . April 19 . . . . . . . . . . . . 8 87 56 71.2

April 12 . . . . . . . . . . . . . April . . . . . . . . . . . . 10 87 56 72_8

April 13 . . . . . . . . . . . . . April 28 . . . . . . . . . . . . 15 87 52 72_9

April 14 . . . . . . . . . . . . . April 26 . . . . . . . . . . . . 12 87 56 73.0

April 15 . . . . . . . . . . . . . April 27 . . . . . . . . . . . . 12 87 56 73_()

April 16 . . . . . . . . . . . . . April 29 . . . . . . . . . . .. 13 87 52 71_4

April 20 . . . . . . . . . . . . . May 1 . . . . . . . . . . . . 11 87 52 71.0

April 23 . . . . . . . . . . . . . May 2 . . . . . . . . . . . . 9 87 52 71.1

April 26 . . . . . . . . . . . . . May 3 . . . . . . . . . . . . 7 86 52 69.1

April 29 . . . . . . . . . . . . . May 8 . . . . . . . . . . . . 9 99 59 75,3

April 30 . . . . . . . . . . . . . May 7 . . . . . . . . . . . . 7 96 65 75.4

May 2. .‘ . . . . . . . . . . . May 9 . . . . . . . . . . .. 7 100 65 79.4

May 3 . . . . . . . . . . . . . May 10 . . . . . . . . . . .. 7 100 66 82.2

May 3 . . . . . . . . . . . . . May 10 . . . . . . . . . . .. 7 100 66 82.2

May 4 . . . . . . . . . . . .. May _10 . . . . . . . . . . .. 6 i100 73 84.3

May 4 . . . . . . . . . . . .. May 9 . . . . . . . . . . .. 5 100 73 83.3

May 4 . . . . . . . . . . - . .. May 11 . . . . . . . . . . .. 7 100 73 85.0

May 5 . . . . . . . . . . . .. May 11 . . . . . . . . . . .. 6 100 74 86.6

May 5 . . . . . . . . . . . .. May 11 . . . . . . . . . . .. 6 100 74 86.6

May 5 . . . . . . . . . . . .. May 11 . . . . . . . . . . .. 6 100 74 86.6

May 5 . . . . . . . . . . . .. May 12 . . . . . . . . . . .. 7 100 74 87.0

May 5 . . . . . . . . . . . .. May 12 . . . . . . . . . . .. 7 100 74 87.0

May 5 . . . . . . . . . . . .. May 13 . . . . . . . . . . .. 8 100 74 87.2

May 6 . . . . . . . . . . . . . May 13 . . . . . . . . . . .. 7 100 76_ 88.0

May 6 . . . . . . . . . . . .. May 13 . . . . . . . . . . .. 7 100 76 88.0

May 7 . . . . . . . . . . . .. May 14 . . . . . . . . . . .. 7 100 80 88.5

May 7 . . . . . . . . . . . .. May 14 . . . . . . . . . . .. 7 100 80 88.5

May 7 . . . . . . . . . . . .. May 1:) . . . . . . . . . . .. 8 100 80 88.3

May 8 . . . . . . . . . . . .. May 15 . . . . . . . . . . .. 7 100 8O 88.7

May 8 . . . . . . . _ . . . .. May 16 . . . . . . . . . . . . 8 100 74 88.5

May 9 . . . . . . . . . . . .. May 18 . . . . . . . . . . .. 9 98 70 89.4

May 9 . . . . . . . . . . . . . May 19 . . . . . . . . . . .. 10 98 70 86.2

May 10 . . . . . . . . . . . . . May 20 . . . . . . . . . . .. 10 98 70 84.5

May 11 . . . . . . . . . . . .. May 23 . . . . . . . . . . .. 12 97 70 83.2

May 12 . . . . . . . . . . . . . May 24 . . . . . . . . . . . . 12 97 70 82.5

May 13 . . . . . . . . . . . .. May 24 . . . . . . . . . . .. 11 97 70 82.0

May 14 . . . . . . . . . . . . . May 25 . . . . . . . . . . .. 11 97 70 81.1

May 17 . . . . . . . . . . . .. May 27 . . . . . . . . . . .. 10 91 70 79.4

May 18 . . . . . . . . . . . . . May 25 . . . . . . . . . . . . 7 91 70 78.5

May 19 . . . . . . . . . . . .. May 27 . . . . . . . . . . .. 8 91 71 79.7

May 22 . . . . . . . . . . . .. May 27 . . . . . . . . . . .. 5 91 71 80.8

May 22 . . . . . . . . . . . .. May 28 . . . . . . . . . . .. 6 89 71 80.5

May 23 . . . . . . . . . . . .. May 28 . . . . . . . . . . .. 5 89 71 80.9

May 23 . . . . . . . . . . . .. May 28 . . . . . . . . . . .. 5 89 71 80.9

May 24 . . . . . .  May 30 . . . . . . . . . . .. 6 89 73 80.4

May 24 . . . . . . . . . . . .. lVIay 31 . . . . . . . . . . .. 7 94 73 80.5

May 25 . . . . . . . . . . . . . May 31 . . . . . . . . . . . . 6 94 73 80.8

May 27 . . . . . . . . . . . .. June 1 . . . . . . . . . . .. 5 94 73 80.1

May 28 . . . . . . . . . . . .. June 2 . . . . . . . . . . .. 5 94 73 82.0

May 29 . . . . . . . . . . . .. June 3 . . . . . . . . . . .. 5 94 74 82.8

May 30 . . . . . . . . . . . . . June 4 . . . . . . . . . . . . 5 94 77 83.8

May 31 . . . . . . . . . . . .. June 5 . . . . . . . . . . .. 5 92 77 84.5

June 1 . . . . . . . . . . . .. June 6 . . . . . . . . . . .. 5 93 78 83.9

June 1 . . . . . . . . . . . .. June 7.. 6 94 76 84.3

June 2 . . . . . . . . . . . .. June 8 . . . . . . . . . . .. 6 94 71 84.7

June 3 . . . . . . . . . . . .. June 9 . . . . . . . . . . .. 6 94 71 83.3

June  June10 . . . . . . . . . . .. 6 94 71 82.5

June 4 . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 7 94 71 83.0

June 5 . . . . . . . . . . . . . June 12 . . . . . . . . . . .. 7 94 71 82.8

June 5 . . . . . . . . . . . .. June 12 . . . . . . . . . . .. 7 94 71 82.8

June 6 . . . . . . . . . . . . . June 13 . . . . . . . . . . .. 7 94 71 83.0

June 6 . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 7 94 71 83.0

June 6 . . . . . . . . . . . .. June 14 . . . . . . . . . . .. 8 94 71 82.7

June 7 . . . . . . . . . . . . . June 14 . . . . . . . . . . .. 7 90 71 82.2

June 8 . . . . . . . . . . . .. June 14 . . . . . . . . . . .. 6 90 72 81.8

June  June15 . . . . . . . . . . .. 6 90 73 83.5

June l0 . . . . . . . . . . . .. June 16 . . . . . . . . . . .. 6 90 72 84.0

June 11 . . . . . . . . . . . .. June 17 . . . . . . . . . . .. 6 89 72 82.5

June 12 . . . . . . . . . . . .. June 18 . . . . . . . . . . . . 6 89 72 82.1

June 13 . . . . . . . . . . . .. June 19 . . . . . . . . . . .. 6 89 72 81.6

June 14 . . . . . . . . . . . .. June 21 . . . . . . . . . . . . 7 95 72 82.0

THE OQWPEA WEEVIL.

Table 11.—Duration of Pupal Stage.-—Continued.

33

Temperature
Pupated Emerged Period _ .
Max Mm. Mean
1916
June 15 . . . . . . . . . . . .. June 20 . . . . . . . . . . .. 5 95 72 81.0

June 16 . . . . . . . . . . . .. June 22 . . . . . . . . . . .. 6 95 74 82.0

June 17 . . . . . . . . . . . .. June 23 . . . . . . . . . . .. 6 95 75 83.5

June 18 . . . . . . . . . . . .. June 24 . . . . . . . . . . .. 6 . _ 95 75 84.1

June 19 . . . . . . . . . . . .. June 25 . . . . . . . . . . .. 6 95 75 85.0

June 21 . . . . . . . . . . . .. June 26 . . . . . . . . . . .. 5 95 80 86.7

June 22 . . . . . . . . . . . .. June 27 . . . . . . . . . .. 5 95 80 86.8

June 23 . . . . . . . . . . . . . June 28 . . . . . . . . . . .. 5 95 75 87.2

June 24 . . . . . . . . . . . . . June 29 . . . . . . . . . . .. 5 95 75 87.0

June 25 . . . . . . . . . . . . . June 30 . . . . . . . . . . .. 5 95 75 86.6

June 26 . . . . . . . . . . . .. July 1 . . . . . . . . . . .. 5 95 75 85.6

June 27 . . . . . . . . . . . .. July 2 . . . . . . . . . . .. 5 95 75 85.0

June 28 . . . . . . . . . . . . . July 2 . . . . . . . . . . . . 4 93 76 84.2

June 29.. r July 3 . . . . . . . . . . .. 4 93 76 84.2

June O . . . . . . . . . . . . . July 4 . . . . . . . . . . .. 4 93 76 84.2

July 1 . . . . . . . . . . . . . July 4, . . . . . . . . . . . . 3 93 76 84. 6

July 2 . . . . . . . . . . . . . July 6 . . . . . . . . . . .. 4 95 76 85.2

July 2 . . . . . . . . . . . .. July 7 . . . . . . . . . . .. 5 97 76 85.5

July 4 . . . . . . . . . . . .. July 9 . . . . . . . . . . .. 5 99 77 87.2

July 4 . . . . . . . . . . . .. July 1O . . . . . . . . . . .. 6 99 77 87.5

July 5 . . . . . . . . . . . .. July 11 . . . . . . . . . . .. 6 99 79 88.1

July 6 . . . . . . . . . . . .. July 12 . . . . . . . . . . .. 6 99 79 88.5

July 7 . . . . . . . . . . . .. July 13 . . . . . . . . . . .. 6 99 79 88.1

July 8 . . . . . . . . . . . .. July 14 . . . . . . . . . . .. 6 98 79 87.8

July 9 . . . . . . . . . . . .. July 6 . . . . . . . . . . .. 7 98 79 87.2

July 1O . . . . . . . . . . . .. July 17 . . . . . . . . . . .. 7 98 79 87. 1

July 11 . . . . . . . . . . . .. July 17 . . . . . . . . . . .. 6 98 79 86.8

July 12 . . . . . . . . . . . .. July 18 . . . . . . . . . . .. 6 99 79 87.0

July 13 . . . . . . . . . . . .. July 19 . . . . . . . . . . .. 6 99 79 87.6

July 14 . . . . . . . . . . . .. July 20 . . . . . . . . . . .. 6 99 79 87.5

July 15 . . . . . . . . . . . .. July 20 . . . . . . . . . . .. 5 99 79 85.2

July 16 . . . . . . . . . . . .. July 21 . . . . . . . . . . .. 5 99 78 88.0

July 17 . . . . . . . . . . . .. July 21 . . . . . . . . . . .. 4 99 78 88.0

July 18 . . . . . . . . . . . .. July 23 . . . . . . . . . . .. 5 97 8O 88.2

July 19 . . . . . . . . . . . .. July 24 . . . . . . . . . . .. 5 99 80 87. 6

July 20 . . . . . . . . . . . .. July 25 . . . . . . . . . . .. 5 99 80 88.6

July 2O . . . . . . . . . . . .. July 26 . . . . . . . . . . .. 6 99 78 88.6

July 22 . . . . . . . . . . . .. July 27 . . . . . . . . . . .. 5 99 78 88.2

July 23 . . . . . . . . . . . .. July 27 . . . . . . . . . . .. 4 99 78 87.5

July 24. July 3O . . . . . . . . . . .. 6 98 78 85.8

July 27 . . . . . . . . . . . .. Aug. 1 . . . . . . . . . . .. 5 97 78 85.8

July 27 . . . . . . . . . . . .. Aug. 2 . . . . . . . . . . .. 6 97 78 86.3

July 28 . . . . . . . . . . . .. Aug. 2 . . . . . . . . . . .. 5 97 78 86.6

July 28 . . . . . . . . . . . .. Aug. 3 . . . . . . . . . . .. 6 97 78 86.8 '

July 29 . . . . . . . . . . . .. Aug. 4 . . . . . . . . . . .. 6 97 78 87.6

July 30 . . . . . . . . . . . .. Aug 5 . . . . . . . . . . .. 6 97 79 88.0

July 31 . . . . . . . . . . . .. Aug. 6 . . . . . . . . . . .. 6 97 79 87.8

Aug. 1 . . . . . . . . . . . . . Aug. 7 . . . . . . . . . . . . 6 97 79 87.1

Aug. 2 . . . . . . . . . . . . . Aug. 8 . . . . . . . . . . . . 6 97 79 86.5

Aug. 3 . . . . . . . . . . . . . Aug. 9 . . . . . . . . . . . . 6 96 79 86. 1

Aug. 4 . . . . . . . . . . . . .. Aug 10 . . . . . . . . . . .. 6 96 78 85.5

Aug. 5 . . . . . . . . . . . .. Aug 11 . . . . . . . . . . .. 6 95 78 85.0

Aug. 6 . . . . . . . . . . . .. Aug 12 . . . . . . . . . . .. 6 95 78 84.3

Aug. 8 . . . . . . . . . . . .. Aug 13 . . . . . . . . . . .. 5 95 78 85.4

Aug. 9 . . . . . . . . . . . .. Aug 14 . . . . . . . . . . .. 5 96v 78 85.6

Aug 10 . . . . . . . . . . . .. Aug 16 . . . . . . . . . . .. 6 96 79 86.1

Aug 11 . . . . . . . . . . . .. Aug 17 . . . . . . . . . . .. >6 96 75 86.8

Aug 12 . . . . . . . . . . . .. Aug 18 . . . . . . . . . . .. 6 96 75 86.3

Aug 13 . . . . . . . . . . . .. Aug 19 . . . . . . . . . . .. 6 96 75 86.1

Aug 14 . . . . . . . . . . . .. Aug 2O . . . . . . . . . . .. 6 95 75 86.2

Aug 16 . . . . . . . . . . . .. Aug. 20 . . . . . . . . . . .. 4 94 75 85.7

Aug 17 . . . . . . . . . . . .. Aug. 21 . . . . . . . . . . .. 4 100 8O 85.7

Aug 17.. Aug 22 . . . . . . . . . . .. 5 100 80 86.8

Aug 18.. Aug 23 . . . . . . . . . . .. 5 100 80 88.0

Aug 19 . . . . . . . . . . . .. Aug. 25 . . . . . . . . . . .. 6 100 73 87.8

Aug 20 . . . . . . . . . . . . . Aug. 26 . . . . . . . . . . . . 6 100 7O 87.0

Aug. 20 . . . . . . . . . . . . . . Aug. 27 . . . . . . . . . . . . 6 100 7O 86.2

Aug. 21 . . . . . . . . . . . . . Aug. 27 . . . . . . . . . . . . 6 97 70 86. 1

Aug. 22 . . . . . . . . . . . . . Aug. 28'. . . . . . . . . . . . 6 96 70 84.6

Aug. 25 . . . . . . . . . . . .. Aug. 31 . . . . . . . . . . .. ’ 6 97 7O 84.0

Aug. 26 . . . . . . . . . . . .. Aug. 31 . . . . . . . . . . .. 5 97 75 84.4

Aug. 28 . . . . . . . . . . . . . Sept. 1 . . . . . . . . . . . . 4 97 77 86.2

Aug 29 . . . . . . . . . . . .. Sept 2 . . . . . . . . . . .. 4 97 78 86.0

Aug 30 . . . . . . . . . . . .. Sept 4 . . . . . . . . . . .. 5 97 78 86.8

Aug. 31 . . . . . . . . . . . .. Sept 4 . . . . . . . . . . .. 4 97 79 87.2

Sept 1 . . . . . . . . . . . . . Sept 5 . . . . . . . . . . . . 4 97 80 87. 5

Sept. 2 . . . . . . . . . . . .. Sept 5 . . . . . . . . . . .. 3 97 8O 88.0

Sept. 2 . . . . . . . . . . . .. Sept 6 . . . . . . . . . . .. 4 97 80 88.2

Sept. 3 . . . . . . . . . . . .. Sept 7 . . . . . . . . . . .. 4 97 8O 88.5

TEXAS AGRICULTURAL EXPERIMENT STATION.

34
Table 11.—Duration of Pupal Stage.—-Continued.
_ Temperature
Pupated Emerged Perlod _
Max Mm. Mean
1916

Sept. 5 . . . . . . . . . . . . . Sept. 10 . . . . . . . . . . . . 5 101 8O 89.2

Sept 7 . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . 4 101 80 89.0

Sept 8 . . . . . . . . . . . . . Sept. 12 . . . . . . . . . . . . 4 99 80 89.0

Sept 10 . . . . . . . . . . . . . Sept. 13 . . . . . . . . . . . . 3 97 79 88.0

Sept 11 . . . . . . . . . . . . . Sept. 14 . . . . . . . . . . . . 3 96 78 88.0

Sept 11 . . . . . . . . . . . . . Sept. 14 . . . . . . . . . . . . 3 96 78 88.0

Sept 12 . . . . . . . . . . . . . Sept. 17 . . . . . . . . . . . . 5 97 70 84.2

Sept 13 . . . . . . . . . . . .. Sept. 18 . . . . . . . . . . . . 5 99 67 82.2

Sept 14 . . . . . . . . . . . . . Sept. 19 . . . . . . . . . . . . 5 99 67 81.2

Sept 14 . . . . . . . . . . . . . Sept. 20 . . . . . . . . . . . . 6 99 67 80.8

Sept 16 . . . . . . . . . . . . . Sept. 20 . . . . . . . . . . . . 4 99 67 79.4

Sept 17 . . . . . . . . . . . . . Sept. 22 . . . . . . . . . . . . 5 99 67 80.2

Sept 18 . . . . . . . . . . . . . Sept. 24 . . . . . . . . . . . . 6 91 68 80.5

Sept 19 . . . . . . . . . . . . . Sept. 26 . . . . . . . . . . . . 7 91 69 80. 5

Sept 20 . . . . . . . . . . . . . Sept. 27 . . . . . . . . . . . . 7 105 70 80.2

Sept 23 . . . . . . . . . . . . . Sept. 28 . . . . . . . . . . . . 5 105 71 80.2

Sept. . . . . . . . . . . . . . Sept. 29 . . . . . . . . . . . . 5 105 60 85.2

Sept. 25 . . . . . . . . . . . . . Sept. 29 . . . . . . . . . . . . 4 105 60 83. 7

Sept 27 . . . . . . . . . . . . . Oct. 4 . . . . . . . . . . . . 7 95 57 77.7

Sept 28 . . . . . . . . . . . . . Oct". 5 . . . . . . . . . . . . 7 89 57 74.5

Sept 30 . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 7 89 59 74.1

Oct. 2 . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 5 89 64 77. 0

Oct. 3 . . . . . . . . . . . . . Oct. 8 . . . . . . . . . . . . 5 90 66 77.6

Oct. 4 . . . . . . . . . . . . . Oct. 9 . . . . . . . . . . . . 5 91 66 78.0

Oct. 5 . . . . . . . . . . . . . Oct. 11 . . . . . . . . . . . . 6 94 68 79.0

Oct. 6 . . . . . . . . . . . . . Oct. 11 . . . . . . . . . . . . 5 94 68 79.2

Oct. 7 . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 5 94 68 79.4

Oct. ' 8 . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 5 94 68 79.6

Oct. L8 . . . . . . . . . . . . . , Oct. 13 . . . . . . . . . . . . 5 94 68 79.6

Oct. 9 . . . . . . . . . . . . . Oct. 14 . . . . . . . . . . . . 5 94 68 79. 8

Oct. 11 . . . . . . . . . . . . . Oct. 16 . . . . . . . . . . . . 5 90 65 79.6

Oct. 12 . . . . . . . . . . . . . Oct. 17 . . . . . . . . . . . . 5 90 65 79.2

~Oct. 13 . . . . . . . . . . . . . Oct. 17 . . . . . . . . . . . . 4 90 65 79.5

-Oct. 13 . . . . . . . . . . . . . Oct. 19 . . . . . . . . . . . . 6 90 60 76. 5

Oct.‘ 14 . . . . . . . . . . . .. Oct. 23 . . . . . . . . . . . . 9 87 41 70.0

~Oct.j15 . . . . . . . . . . . . . Oct. 24 . . . . . . . . . . . . 9 95 41 68.7

OctJ 16 . . . . . . . . . . . . . Oct. 24 . . . . . . . . . . . . 8 95 41 67.6

Oct] 17 . . . . . . . . . . . . . Oct. 28 . . . . . . . . . . . . 11 95 41 68.8

Oct] 18 . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 11 95 41 68. 6

Oct.; 21 . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 8 95 52 69. 3

Octal 22 . . . . . . . . . . . . . Oct. 30 . . . . . . . . . . . . 8 95 53 71.3

Octx, 23 . . . . . . . . . . . . . Oct. 31 . . . . . . . . . . . . 8 95 53 73. 1

Oct. 25 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . . . 7 92 53 73.8

Oct. [.28 . . . . . . . . . . . . . Nov. 2 . . . . . . . . . . . . 5 90 60 76.7

Oct. [29 . . . . . . . . . . . . . Nov. 4 . . . . . . . . . . . . 6 90 60 76.8

~Oct. 30 . . . . . . . . . . . . . Nov. 4 . . . . . . . . . . . . 5 89 60 77.0

~Oct. 31 . . . . . . . . . . . . . ‘Nov. 8 . . . . . . . . . . . . 8 89 60 76.6

.Nov. 1 . . . . . . . . . . . . . Nov. 8 . . . . . . . . . . . . 7 89 60 75. 7

.Nov. 4 . . . . . . . . . . . . . Nov. 12 . . . . . . . . . . . . 8 87 54 74.0

iNov. 5 . . . . . . . . . . . . . Nov. 12 . . . . . . . . . . . . 7 87 51 72.8

Nov. 5 . . . . . . . . . . . . . Nov. 21 . . . . . . . . . . . . 16 94 33 67. 5

Nov. f 6 . . . . . . . . . . . . . Nov. 21 . . . . . . . . . . . . »15 94 33 66.8

Nov. 16 . . . . . . . . . . . . . Dec 2 . . . . . . . . . . . . 16 98 44 67.8

Nov. 18 . . . . . . . . . . . . . Dec 3 . . . . . . . . . . . . 15 94 44 69.0

Nov. 20 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 15 101 44 76.6

Nov. 24 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 11 101 44 71.6

Nov. 25 . . . . . . . . . . . . . Dec 6 . . . . . . . . . . . . 11 101 44 73.7

Nov. 25 . . . . . . . . . . . . . Dec 12 . . . . . . . . . . . . 17 101 44 72.2

Nov. 26 . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 12 101 48 75.8

Nov. 26 . . . . . . . . . . . . . Dec. 9 . . . . . . . . . . . . 13 101 38 75.4

Nov. 27‘ . . . . . . . . . . . . . Dec 9 . . . . . . . . . . . . 12 101 38 76.3

Nov. 28 . . . . . . . . . . . . . Dec 1O . . . . . . . . . . .. 12 101 38 75.5

Nov. 28 . . . . . . . . . . . . . Dec 10 . . . . . . . . . . . . 12 101 38 75.5

.Nov. 29 . . . . . . . . . . . . . Dec 14 . . . . . . . . . . . . 15 101 32 77.8

Nov. 30 . . . . . . . . . . . .. Dec 17 . . . . . . . . . . .. 17 101 32 73.9

Dec. 1 . . . . . . . . . . . . . Dec 18 . . . . . . . . . . . . 17 101 34 68.1

Dec. 3 . . . . . . . . . . . . . Dec 24 . . . . . . . . . . . . 21 101 28 63.1

Dec. 4 . . . . . . . . . . . . . Dec 25 . . . . . . . . . . . . 21 101 28 62.7

Dec. 5 . . . . . . . . . . . . . Dec 25 . . . . . . . . . . . . 20 99 28 61.2

Dec. 6 . . . . . . . . . . . . . Dec 31 . . . . . . . . . . . . 25 90 28 61.2

Dec. 7 . . . . . . . . . . . . . Jan. 1 . . . . . . . . . . . . 25 90 28 59. 8

Dec. 8 . . . . . . . . . . . . . an. 3 . . . . . . . . . . . . 26 92 28 60.0

Decx 11 . . . . . . . . . . . . . Jan. 5 . . . . . . . . . . . . 25 92 28 58. 6

Dec. 12 . . . . . . . . . . . . . Jan 7 . . . . . . . . . . . . 26 92 28 59.3

Dec. 17 . . . . . . . . . . . .. Jan 9 . . . . . . . . . . . . 23 92 28 59.6

Dec. . . . . . . . . . . . . . Jan. 18 . . . . . . . . . . . . 25 92 30 59.0

Dec. 25 . . . . . . . . . . . . . Jan. 26. _. . . . . . . . . . . 32 92 30 57.4

THE COWPEA YVEEVIL. 35
Table lL-Duration of Pupal Stage.-——Continued.
. Temperature
Pupated Emerged Period _
Max Mm. Mean
1917

an. 2 . . . . . . . . . . . .. Jan. 27 . . . . . . . . . . . . 25 94 3O 55. 6

Jan. 2 . . . . . . . . . . . .. Jan. 29 . . . . . . . . . . .. 27 94 3O 56.0

Jan 2 . . . . . . . . . . . .. Feb. 2 . . . . . . . . . . . . 31 100 25 57.0

Jan 3 . . . . . . . . . . . . . Feb. 5 . . . . . . . . . . . . 33 100 25 58.4

Jan 4 . . . . . . . . . . . . . Feb. 10 . . . . . . . . . . .. 37 100 25 60.6

Jan 5 . . . . . . . . . . . .. Feb. 11 . . . . . . . . . . .. 37 100 25 60. 6

Jan 6 . . . . . . . . . . . .. Feb. 13. . . . . . . . . . .. 38 100 25 60.0

Jan 6 . . . . . . . . . . . .. Feb. 15 . . . . . . . . . . .. 40 100 25 60.2

Jan 7 . . . . . . . . . . . .. Feb. 15 . . . . . . . . . . .. 39 100 25 59. 9

Jan 7 . . . . . . . . . . . . . Feb. 18 . . . . . . . . . . .. 42 100 25 59.8

Jan 10 . . . . . . . . . . . .. Feb. 16 . . . . . . . . . . .. 37 100 25 63.0

Jan 11 . . . . . . . . . . . .. Feb. 18 . . . . . . . . . . .. 38 100 25 60.5

Jan 26 . . . . . . . . . . . . . Feb. 20 . . . . . . . . . . . . 25 100 25 65. 6

Jan 27 . . . . . . . . . . . .. Feb. 17 . . . . . . . . . . .. 21 100 25 69.5

Jan 27 . . . . . . . . . . . . . Mar. 6 . . . . . . . . . . . . 38 103 25 56.0

Jan 28 . . . . . . . . . . . . . Feb. 21 . . . . . . . . . . . . 24 100 25 53.0

Jan 29 . . . . . . . . . . . . . Feb. 21 . . . . . . . . . . . . 23 100 25 53. 0

Jan 29 . . . . . . . . . . . . . Feb. 22 . . . . . . . . . . . . 24 103 25 53.1

Jan 30 . . . . . . . . . . . . . Feb. 22 . . . . . . . . . . . . 23 103 25 52.0

Jan 30 . . . . . . . . . . . . . Feb. 23 . . . . . . . . . . . . 24 103 25 53. 0

Jan 31 . . . . . . . . . . . . . Feb. 25 . . . . . . . . . . . . 25 103 25 55.4

Feb. 6 . . . . . . . . . . . . . Feb. 25 . . . . . . . . . . . . 19 103 4O 57.8

Feb 13 . . . . . . . . . . . . .. Feb. 27 . . . . . . . . . . . . 14 103 41 58.2

Feb 17 . . . . . . . . . . . . . Mar. 1 . . . . . . . . . . . . 12 103 41 65.8

Feb 20 . . . . . . . . . . . . . Mar. 7 . . . . . . . . . . . . 15 103 33 64. 5

Feb 21 . . . . . . . . . . . . . Mar. 11 . . . . . . . . . . . . 18 103 33 65.2

Feb 24 . . . . . . . . . . . . . Mar. 15 . . . . . . . . . . . . 19 102 33 66.3

Feb 25 . . . . . . . . . . . . . Mar. 13 . . . . . . . . . . . . 16 102 33 66.4

Feb 25 . . . . . . . . . . . . . Mar. 13 . . . . . . . . . . . . 16 102 33 66.4

Feb 26 . . . . . . . . . . . .. Mar. 15 . . . . . . . . . . .. 17 102 33 61.3

Feb 26 . . . . . . . . . . . .. Mar. 15 . . . . . . . . . . .. 17 102 33 61.3

Feb 26 . . . . . . . . . . . . . Mar. 19 . . . . . . . . . . . . 21 ,102 33 66.1

Feb 26 . . . . . . . . . . . . . Mar. 23 . . . . . . . . . . . . 25 102 33 67. 6

Feb 27 . . . . . . . . . . . . . Mar. 14 . . . . . . . . . . . . 15 100 33 67.3

Feb 28 . . . . . . . . . . . . . Mar. 14 . . . . . . . . . . . . 14 91 33 64. O

Feb 28 . . . . . . . . . . . . . Mar. 16 . . . . . . . . . . . . 16 92 33 64. 5

Feb 28 . . . . . . . . . . . . . Mar. 16 . . . . . . . . . . . . 16 .92 33 64.5

Feb 28 . . . . . . . . . . . . . Mar. 17 . . . . . . . . . . . . 17 92 33 65.3

Feb 28 . . . . . . . . . . . . . Mar. 17 . . . . . . . . . . . . 17 92 33 65.3

Mar 1 . . . . . . . . . . . . . Mar. 16 . . . . . . . . . . . . 15 92 33 63. 8

Mar 1 . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 19 92 33 63.6

Mar 2 . . . . . . . . . . . . . Mar. 17 . . . . . . . . . . . . 15 92 33 63.5

Mar 2 . . . . . . . . . . . .. Mar. 18 . . . . . . . . . . .. l6 92 33 63.2

Mar 2 . . . . . . . . . . . . . Mar. 18 . . . . . . . . . . . . 16 92' 33 63.2

Mar 2 . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 18 92 33 64.0

Mar 2 . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 18 92 33 64.0

Mar 2 . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 18 92 33 64.0

Mar 3 . . . . . . . . . . . . . Mar. 20 . . . . . . . . . . . . 17 92 33 63.8

Mar 3 . . . . . . . . . . . .. Mar. 21 . . . . . . . . . . .. 18 92 33 64.3

Mar 4 . . . . . . . . . . . . . Mar. 21 . . . . . . . . . . . . 17 92 33 64.7

Mar 6 . . . . . . . . . . . .. Mar. 21 . . . . . . . . . . .. 15 92 47 66.4

Mar 8 . . . . . . . . . . . . . Mar. 22 . . . . . . . . . . . . 14 99 49 66. 3

Mar 8 . . . . . . . . . . . . . Mar. 22 . . . . . . . . . . . . 14 99 49 66.3

Mar. 11 . . . . . . . . . . . . . Mar. 25 . . . . . . . . . . . . 14 99 49 69.1

Mar. 12 . . . . . . . . . . . . . Mar. 26 . . . . . . . . . . . . 14 99 49 69.2

Mar. 14 . . . . . . . . . . . . . Mar. 26 . . . . . . . . . . . . 12 99 49 70.0

Mar. 15 . . . . . . . . . . . . . . Mar. 26 . . . . . . . . . . . . ll 99 49 69.4

Mar. 15 . . . . . . . . . . . . . . Mar. 29 . . . . . . . . . . . . 14 99 49 67.4

Mar. 16 . . . . . . . . . . . .. Mar. 28 . . . . . . . . . . . . 12 99 49 68.2

Mar. 16 . . . . . . . . . . . .. Mar. 28 . . . . . . . . . . .. 12 99 49 68.2

Mar. 19 . . . . . . . . . . . .. Mar. 31 . . . . . . . . . . .. 12 99 50 70.0

Mar. 20 . . . . . . . . . . . . . Mar. 30 . . . . . . . . . . . . 10 99 50 69.7

Mar. 20 . . . . . . . . . . . . . Mar. 31 . . . . . . . . . . . . ll 99 50 69.9

Mar. 20 . . . . . . . . . . . . . Mar. 31 . . . . . . . . . . . . 11 99 50 69. 9

Mar. 20 . . . . . . . . . . . . .. M31‘. 31 . . . . . . . . . . .. 11 99 5O 69.9

Mar. 2O . . . . . . . . . . . . . Aprll 1 . . . . . . . . . . . . 12 99 50 75. 7

Mar. 20 . . . . . . . . . . . . . Aprll 6 . . . . . . . . . . . . 17 102 5O 71,2

Mar. 21 . . . . . . . . . . . . . Mar. 30 . . . . . . . . . . . . 9 99 50 69.6

Mar. 21 . . . . . . . . . . . .. Mar. 31 . . . . . . . . . . . . 10 99 50 70.9

Mar. 21 . . . . . . . . . . . . . . April 2 . . . . . . . . . . . . 12 102 50 71.7

Mar. 21 . . . . . . . . . . . .. Aprll 4 . . . . . . . . . . .. 14 102 50 71.3

Mar. 22 . . . . . . . . . . . . . M31‘. 31 . . . . . . . . . . . . 9 99 50 69.1

Mar. 22 . . . . . . . . . . . . . Aprgl 4 . . . . . . . . . . . . 13 102 50 70_ 0

Mar. 22 . . . . . . . . . . . . . . Aprll 6 . . . . . . . . . . . . 15 102 50 70. 0

Mar. 24 . . . . . . . . . . . . . . Aprll 5 . . . . . . . . . . . . 12 102 5O 74,8

Mar. 24 . . . . . . . . . . . . . . Aprll 5 . . . . . . . . . . . . 12 102 5O 74, 8

Mar. 24 . . . . . . . . . . . . . . Apryl 6 . . . . . . . . . . . . 13 102 50 62. 5

Mar. 25 . . . . . . . . . . . . . . Aprgl 5 . . . . . . . . . . . . ll 102 50 69.7

Mar. 25 . . . . . . . . . . . . . Aprll 7 . . . . . . . . . . . . 13 102 50 62.2

36 TEXAS AGRICULTURAL EXPERIMENT STATION.‘

Table 11.—Duration of Pupal Stage-Continued.

 

_ Temperature
Pupated Emerged Period _
_ Max. Min. Mean
Mar. 25 . . . . . . . . . . . . . April 10 . . . . . . . . . . . . 16 102 50 69.5

Mar. 26 . . . . . .‘ . . . . . .. April 6 . . . . . . . . . . . . 11 102 50 69.2

Mar. 26 . . . . . . . . . . . . . April 8 . . . . . . . . . . . . 13 ' 102 50 69.5

Mar. 26 . . . . . . . . . . . .. April 15 . . . . . . . . .  . 20 102 5O 69.1

Mar. 27. .5 . . . . . . . . . . . April 7 . . . . . . . . . . . . 11 102 50 70.1

Mar. 28 . . . . . . . . . . . .. April 10 . . . . . . . . . . .. 13 102 51 70.7

Mar. 29 . . . . . . . . . . . .. April 10 . . . . . . . . . . .. 12 102 51 71.5

Mar. 30 . . . . . . . . . . . .. April 10 . . . . . . . . . . .. 11 102 51 70.7

Mar. 3O . . . . . . . . . . . .. April 12 . . . . . . . . . . .. 13 102 51 70.0

Mar. 3O . . . . . . . . . . . .. April 14 . . . . . . . . . . . . 15 102 51 70. 1

Mar. 31 . . . . . . . . . . . .. April16 . . . . . . . . . . .. 16 102 51 %.0

April 5,3 . . . . . . . . . . . .. April 19 . . . . . . . . . . .. 16 90 51 .9

The shortest pupal period of three days occurred three times in
November, 1915, once in March, 191.6, and four times in September,
1916. During November this period occurred with a mean tempera-
ture of 76.9 degrees F. This period in March occurred with a mean
temperature of but 741.11 degrees F. The maximum temperature of the
period was 89 degrees F. and the minimum was 60 degrees F. In
September, when the pupal stage was but three days, the mean tempera-
ture was 87.6 degrees F. The longest pupal period of 53 days occurred
from January 5 to February 27, 1916. During this period the mean
temperature was 54.8 degrees; the lowest temperature of the period
was 22 degrees. =

The yearly variation in the duration of the pupal stage is shown in
Table 12. The mean temperature of the period does not have a
positive effect upon its length. The average length of periods is in-
fluenced by a severe low temperature or a fexv days of warm weather.

Table 12.—Yearly Variation in Duration of Pupal Stage.

_ Period Mean
Date (Days) Temperature
_ (Degrees)
November, 1915 . . . . . . . . . . . . . . .. 5.6 75.8

November, 1916 . . . . . . . . . . . . . . . . 12.8 72.3

December, 1915 . . . . . . . . . . . . . . . . 28.1 60.5

December, 1916. ._ . . . . . . . . . . . . .. 23.8 58.9

January, 1916 . . . . . . . . . . . . . . . . .. 41.1 54.4

January, 1917 . . . . . . . . . . . . . . . . .. 31 . 1 57.5

February, 1916 . . . . . . . . . . . . . . . .. ' 28.0 61.4

February, 1917 . . . . . . . . . . . . . . . . . 18. 1 66. 7

A summary of the duration of the pupal stage during the representa-
tive summer months and winter months is given in Table 13. During
the warmest months of the year in this locality the pupal stage com-
prised an average of  days. During the coldest months of the year
the average pupal stage was 21.2 days. The pupal stage was quite
variable throughout each month while the observations were being made.

THE CowrsA WVEEVIL. 37
Table 13.—Summary of Duration of Pupal Stage.
Number
Average Shortest Longest Collections
Month Period Period Period Observed
i June . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. 8 4 8 34

July . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. 5 3 7 32

;_ August . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. 5 4 7 28

._"September . . . . . . . . . . . . . . . . . . . . . . . . 4.4 3 7 25

; November . . . . . . . . . . . . . . . . . . . . . . . . 8.3 4 17 | 48

QDecember . . . . . . . . . . . . . . . . . . . . . . . . 24. 8 4 53 ' 24

é-January . . . . . . . . . . . . . . . . . . . . . . . . . . . - 33.3 24 53 27

i February . . . . . . . . . . . . . . . . . . . . . . . . .i 19.3 12 53 23

t.

E;

 quite noticeable.

The relation of temperature t0 the duration of the pupal stage is‘
The results of the observations are shown in Table 14.

Table 14.—Effect of Temperature on Length of Pupal Stage.

‘i Avera e Mean
Month Perio , Daily
i Days Temperature
- June . . . . . . . . . . . . . . . . . . . . . . . . . .  5. 8 86

July . . . . . . . . . . . . . . . . . . . . . . . . . . . .5. 5 87

August . . . . . . . . . . . . . . . . . . . . . . . . 5 . 5 86

September . . . . . . . . . . . . . . . . . . . . . 4. 4 83

November . . . . . . . . . . . . . . . . . . . ..\ 8.3 71.8

December . . . . . . . . . . . . . . . . . . . . . . 24. 8 62.2

January . . . . . . . . . . . . . . . . . . . . . . . 33. 3 58. 5

February . . . . . . . . . . . . . . . . . . . . . . 19. 3 58. 5

Summaryrdlrom the tables given which show the length of the egg,

Zplarval, and pupal stage, it is evident that the length of these periods
jvaries greatly with the seasons of the year.
jyeach stage combined, may consume about 16 days, however, this total
[was never obtained in any single generation.
were combined, 1'78 days would be required, but no single generation
Econsumed this much time.

The shortest periods of
If all of the long periods

Table 15.—-Summary of Development of Cowpea Weevil.

g “Elongate oval, moderately shining.
p hitish pubescence. ~ Elytra ferruginous or pale brown with large lat-
lral spot and apex broadly bla.ck. Head dark brown or black, densely

Egg, Larva, Pupa, Total
Days Days Days Days
K ortest . . . . . . . . . . . . . . . . . . . . . . .. 4 9 3 ‘ 16
ngést . . . . . . . . . . . . . . . . . . . . . . . . . . 37 88 53 178
Adults.

Descripti0n.-—The cowpea weevil is very closely related to a few

‘ther species of weevils and can hardly be distinguished from them by

ose not familiar with technical details. Any popular description that

, ight be given would hardly allow the proper diagnosis of the exact

ecies of weevil infesting cowpeas or other stored products.

The most comprehensive technical description of this species is that
y Horn, which is given herewith as it occurred in his paper (6) :
Beneath equally clothed with

38 Texas AGRICULTURAL EXPERIMENT STATION.

punctured, front sub-carinate. Antennae as long as head and thorax,
serrate in both sexes, four basal joints pale rufous, outer joints dark
and nearly black. Thorax trapezoidal, broader at base than long, sides
distinctly arcuate, base trisinuate, basal lobe emarginate and clothed
with whitish hairs; color variable from ferruginous to black, coarsely
punctured, sub-granulate and feebly shining, sparsely clothed with
cinereous hair. Scutellum with median impressed line and clothed with
whitish hair. Elytra broader at base than thorax and longer than wide,
sides feebly areuate, humeri moderately prominent; striate, striae
punctured, intervals fiat densely punetulate; color ferruginous with
large lateral spot and apex. black, clothed with whitish and cinereous
pubescence. Pygidium nearly black with median line of whitish
pubescence. Body beneath pieeous densely punctulate and sparsely but
evenly clothed with cinerous hairs; abdomen pale brown. Anterior
and middle legs pale rufous, hind legs pale brown. Hind femora
armed with an acute tooth on the inner side and a broad triangular
tooth on the outer side. Length .12-.18 inch; 3-4.5 mm.”

Most of the specimens are nearly black with four spots of pale brown

A on the wing covers. Many of these spots are outlined with a band of

white. In nearly all specimens the wing covers are clothed with fine
hairs. Sometimes the color of the spot is hidden by a patch of very
fine hairs.

In Plate IV is shown a series of adult weevils. From this plate it
is possible to distinguish the difference in the size of the males and
females. It will also be seen that there is a variation in the size of a
sex. As a rule the females are much larger than the males, but it is
possible to find males that are larger than females. The plates will
also show a variation in the color pattern of the wing covers. By
selection it was possible to produce individuals of either sex with an
absence of spots and with brown wing covers.

Feeding Ilabits of Adults.

The cowpea weevil has not been observed to feed on any solid food
in the adult stage, and the cowpea is injured only by the feeding larva.
Observations show that the adult wreevil never attacks cowpeas directly,
except when emerging, it sometimes gnaws its way through the thin
shell covering the exit of the larval burrow. Frequently the adults re-
enter the larval burrows in the peas and die, giving rise to an erroneous
popular opinion that they feed upon the peas. In the field the adults
feed almost exclusively upon nectar secreted by the nectaries located
at the base of the green pods. A few adults have been collected from
the blossoms of cowpeas. None were observed to visit blossoms of
other plants with any regularity. The adults are egregious in feed-
ing. Invariably single individuals were found feeding; occasionally
two or three were observed at the base of the same pod, but they never
fed in large numbers. The weevils, while feeding, are very active, and
seek shelter very quickly upon the slightest disturbance.

mans H4. Océwmw 3423:“ @5218 wwosmsm <mawmfios m: 2mm 0% mSC $533 3.8 mam 53mm vicar

[Blank Page in Original Bulletin]

THE GoWPEA WEEVIL. 39

Table 16.-—Average Eggs per Female.

Total Average
Date Total Females No. Eggs Mean Mean
Eggs Ovlposltlng Per Temp. Hum

Female

1916 _

January . . . . . . . . . . . . . . 589 23 20 56. 9 ‘ 78.9

February . . . . . . . . . . . . . 190 6 31 55. 0 66.7

arc . . . . . . . ..- . . . . .. 67 14 55 66.4 61.8

April . . . . . . . . . . . . . . . . 1719 29 59 68.9 , 73.0

May . . . . . . . . . . . . . . . .. 2459 30 81 79.6 71.7

June . . . . . . . . . . . . . . . .. 2701 32 8 86.0 71.0

July . . . . . . . . . . . . . . . . . 2546 , 24 106 87. 0 69. 0

August . . . . . . . . . . . . .. 2411 25 96 86.0 68.5

September . . . . . . . . . . . 2635 29 91 83. 5 63. 0

October . . . . . . . . . . . . . . 3243 30 108 73.0 63.5

November . . . . . . . . . . . . 1988 25 80 68. 5 69. 5

December . . . . . . . . . . . . 1758 26 68 64. 6 64.5

Average Eggs Per Female.

The average number of eggs per female, by the month, for 1916, has
been compiled from Table 23 and the results are given in detail in
Table 16. The smallest average number was 25, occurring in January,
with a mean temperature of 56.9 degrees F. The maximum number
of 108, was in October, with a mean temperature of 7'30 degrees F. The
average number of eggs for the entire year was 73, with a mean
temperature of 72.9 degrees F. With a possibility of from 8 to 10
generations of weevils a year and each female capable of producing
an average quota. of 73 eggs, it is not diflicult to realize why this insect
becomes such an important economic factor to the cowpea crop in the
South.

Period From Last‘ Oviposrltion t0 Death 0f Female.

The time which elapses from the last oviposition to the death of the
female varies from 1.7 to 9 days. During the Warm season when the
rate of oviposition is at its maximum, all the eggs are deposited in a
few days and the period from the last oviposition to death of female is
very short. The average time for June and July, 1916, was 1.7 days.
The average minimum period gradually increases as the temperature
decreases. The average maximum period occurred in February, 1916.
For this month 9 days was the average time that occurred from the
last oviposition to the death of the female. The average period for
1916 was 3.4 days with an average mean temperature of 72.9 degrees
F. In Table 17 the detailed results obtatine-d for the period from
October, 1915, to March, 1917, are given.

40 TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 17.——Average Time between Oviposition and Death.

_ Temperature
Year Month Period _ a
Days Max. Mll'1. Mean
1915 . . . . . . . . . .. October . . . . . . . . .. 3.0 78.2 72.0 71.5

1915 . . . . . . . . . .. November . . . . . . . . 3. 0 79. 7 70. 7 74. 7

1915 . . . . . . . . . .. December . . . . . . . . 8.7 67.1 50.6 59.4

1916 . . . . . . . . . .. January . . . . . . . . .. 3.6 65.5 48.3 56.9

1916 . . . . . . . . . . . February . . . . . . . . . 9. 0 65.8 44.3 55.0

1916 . . . . . . . . . .. March . . . . . . . . . .. 3.6 78.1 54.7 66.4

1916 . . . . . . . . . .. April 2. 7 77. 3 59. 7 68. 9

1916 . . . . . . . . . .. May . . . . . . . . . . . .. 2.5 89.4 74.5 79.6

1916 . . . . . . . . . .. June . . . . . . . . . . . .. 1.7 90.3 74.7 86.0

1916 . . . . . . . . . .. "July . . . . . . . . . . . .. 1.7 94.2 79.3 87.0

1916 . . . . . . . . . .. August . . . . . . . . . .. 2. 5 93.3 79. 0 86. 0

1916 . . . . . . . . . .. September . . . . . . .. 3.5 93.0 74.4 83. 5

1916 . . . . . . . . . .. October . . . . . . . . .. 3.1 85.1 61.4 73.0

1916 . . . . . . . . . . . November . . . . . . . . 4.1 84.5 55.5 68.5

1916 . . . . . . . . . . December . . . . . . . . 3. 6 74. 8 50.4 64. 6

1917 . . . . . . . . . .. January . . . . . . . . .. 7.3 68.3 48.1 60.3

1917 . . . . . . . . . . . February . . . . . . . .. 4. 6 76. 8 47. 0 62.0

Table 18.—Difference in Death Rate of Sexes.
~ Male Female Temperature
Emerged Died Died Period
First First Same Mean Mean Average
Max. Mm. Mean
1915

October . . . . . . . . . . . . . 9 2 5 79. 0 70. 1 51.3

November . . . . . . . . . . . 17 0 7 84. 1 68.0 63. 6

December . . . . . . . . . . . 13 2 9 75. 6 38.4 59. 5

January . . . . . . . . . . . .. 3 1 5 76.5 43.0 56.9

February . . . . . . . . . . . . 1 0 1 86. O 39. 0 62. 5

March . . . . . . . . . . . . .. 5 6 2 84.4 47.3 67.6

April . . . . . . . . . . . . . .. 11 7 2 88.2 61.6 75.5

May . . . . . . . . . . . . . . .. 14 7 3 91 9 74.6 62.0

June . . . . . . . . . . . . . . .. 15 3 8 91 4 77.0 75.8

July . . . . . . . . . . . . . . .. 14 9 2 95 8 79,3 84.0

August . . . . . . . . . . . . . . 12 9 4 95 9 78.5 75.5

September . . . . . . . . . . . 19 6 4 93 5 68.4 73.2

October . . . . . . . . . . . . . 17 4 - 9 86 7 56.2 63.3

November . . . . . . . . . . . 12 4 6 87 . 6 50. 5 57. 0

Decegllrer . . . . . . . . . . . 11 9 8 79. 1 44.0 44.2

January . . . . . . . . . .... 13 8 2 93.6 40.9 62 8

Dtfierence in Death Rate of Sexesf

The dilference in longevity of life in the adult weevils, (luring the
period from October, 1915, t0 February, 1917, is given in Table 18.
Out of a total of 340 observations the male died first 186 or 54.7 per
cent. of the time. The female died first in 7'7 instances or 22.6 per
cent. of the time; while both sexes died on the same day in 77 cases
out of the total number of observations, or 22.6 per cent. of the time.
It is interesting to note that the male dies first more than twice as
often as the female. At no time throughout the year do the males live
longer consistently, than the females. There was a tendency, however,
to approach more nearly an equal number of periods when both sexes
died on the same day, during the colder months.

Length of Life 0f Unmated Adults.

The length of life of the unmated individuals was determined as
follows: On August 1, 1916, a pair of unmated weevils were isolated
daily and the death of each individual was noted. These notes were

Tm: COWPEA WEEVIL. 41
made until June, 1917. The results of this experiment are given in
detail in Table 19. The shortest life of the male was 8 days, from
September 5 t0 September 13, 1916; the longest period was 70 days,
from December 14, 1916, to February 22-, 1917. The shortest period
‘for the female was 10 days, which occurred twice, from September 21
to October 1, 1916, and from May 2]. to June 30, 1917; the long-
est period was 69 days, from January 11 to March 21, 1917. It
will be noted that the extremes of the life period for the male are
slightly greater, but that the average life of the female is considerably
longer than that of the male. It is also very apparent that tempera-
ture has a decided influence upon the- length of life. During the
colder months the period is much prolonged.

Table 19.—Length of Life of Unmated Adults.

Period v Period,
Emerged Male Died Days Female Died 7f} Days
1916
Aug. 1 . . . . . . . . . . . . . . Aug 18 . . . . . . . . . . .. 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aug. 2 . . . . . . . . . . . . .. Aug 22 . . . . . . . . . . .. 20 Aug 24 . . . . . . . . . . .. 22

Aug. 3 . . . . . . . . . . . . .. Aug 16 . . . . . . . . . . .. 13 Aug 19 . . . . . . . . . . .. 16

Aug. 4 . . . . . . . . . . . . . . Aug. 16 . . . . . . . . . . .. 12 Aug 23 . . . . . . . . . . .. 19

Aug. 5 . . . . . . . . . . . . .. Aug. 23 . . . . . . . . . . . . 18 Aug 21 . . . . . . . . . . . . 16

Aug. 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Aug 25 . . . . . . . . . . .. 19

Aug. 7 . . . . . . . . . . . . .. Aug. 28 . . . . . . . . . . .. 21 Aug 1 . . . . . . . . . . .. 24

Aug. 8 . . . . . . . . . . . . . . Aug 19 . . . . . . . . . . . . 11 Aug 12—lost . . . . . . .

Aug. 9 . . . . . . . . . . . . . . Sept 2 . . . . . . . . . . . . 24 Sept . . . . . . . . . . . . 25

Aug. 10 . . . . . . . . . . . . . . Sept . . . . . . . . . . . . 38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Aug. 11 . . . . . . . . . . . . .. Sept 16——lost . . . . . . . . . . . . . . . . . Aug 30 . . . . . . . . . . . . 19

Aug. 12 . . . . . . . . . . . . .. Sept 8 . . . . . . . . . . . . 16 Sept 6 . . . . . . . . . . .. 25

Aug. 13 . . . . . . . . . . . . . . Sept 29 . . . . . . . . . . . . 16 Sept 5 . . . . . . . . . . .. 23

Aug. 14 . . . . . . . . . . . . . . Sept. 5 . . . . . . . . . . . . 22 Sept 2 . . . . . . . . . . . . 19

Aug. 15 . . . . . . . . . . . . . . Aug. 29 . . . . . . . . . . . . 14 Sept 2 . . . . . . . . . . . . 18

Aug 16 . . . . . . . . . . . . . . Aug. 30 . . . . . . . . . . . . 14 Sept 11 . . . . . . . . . . . . 26

Aug 17 . . . . . . . . . . . . .. Aug 3O . . . . . . . . . . .. 13 Sept. 2 . . . . . . . . . . .. 16

Aug. 18 . . . . . . . . . . . . .. Sept. 2 . . . . . . . . . . .. 15 Sept. 7 . . . . . . . . . . . . 20

Aug. 19 . . . . . . . . . . . . . . Aug 3O . . . . . . . . . . .. 11 Sept. 11 . . . . . . . . . . .. 19

Aug. 2O . . . . . . . . . . . . . . Sept. 2 . . . . . . . . . . . . 13 Sept 1O . . . . . . . . . . . . 21

Aug. 21 . . . . . . . . . . . . . . Sept. 3 . . . . . . . . . . . . 13 Sept. 13 . . . . . . . . . . . . 23

Aug. 22 . . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . 2O Sept. 15.“ . . . . . . . . . . . 24

Aug. 23 . . . . . . . . . . . . . . Sept. 6 . . . . . . . . . . . . 14 Sept. 7 . . . . . . . . . . . . 15

Aug. 24 . . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . 18 Sept. 2g . . . . . . . . . . . . 29

Aug. 25 . . . . . . . . . . . . . . Sept. 12 . . . . . . . . . . . . 18 Sept. . . . . . . . . . . . . 15

Aug. 26 . . . . . . . . . . . . . . Sept. 8—lost . . . . . . . . . . . . . . . . . Sept 15 . . . . . . . . . . . . 20

Aug. 27 . . . . . . . . . . . . . . Sept. 21 . . . . . . . . . . . . 25 ct. 4 . . . . . . . . . . . . 38

Aug. 28 . . . . . . . . . . . . . . Sept 18 . . . . . . . . . . . . 21 Sept. 20 . . . . . . . . . . . . 23

Aug. 29 . . . . . . . . . . . . . . Sept 7 . . . . . . . . . . . . 9 Sept. 27 . . . . . . . . . . . . 29

Aug. 30 . . . . . . . . . . . . . . Sept 13 . . . . . . . . . . . . 14 Sept. 18 . . . . . . . . . . . . 19

Aug. 31 . . . . . . . . . . . . . . Sept 14 . . . . . . . . . . . . 14 Sept. 26 . . . . . . . . . . . . 26

Sept. 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sept. 18 . . . . . . . . . . . . 17

Sept. 2 . . . . . . . . . . . . . . Sept. 13 . . . . . . . . . . . . 11 Sept 15 . . . . . . . . . . . . 13

Sept. 3 . . . . . . . . . . . . . . Sept. 16 . . . . . . . . . . . . 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sept. 4 . . . . . . . . . . . . . . Sept. 19 . . . . . . . . . . . . 15 Sept. 21 . . . . . . . . . . . . 17

Sept. 5 . . . . . . . . . . . . . . Sept. 13 . . . . . . . . . . . . 8 Sept. 27 . . . . . . . . . . . . 22

Sept. 6 . . . . . . . . . . . . . . Sept‘. 22 . . . . . . . . . . . . 16 Sept. 15—lost . . . . . . . . . . . . . . . . .

Sept. 7 . . . . . . . . . . . . . . Sept 18 . . . . . . . . . . . . 11 Sept. 25 . . . . . . . . . . . . 18

Sept. 8 . . . . . . . . . . . . . . Sept 24 . . . . . . . . . . . . 16 Sept. 27 . . . . . . . . . . . . 19

Sept. 9 . . . . . . . . . . . . . . Sept. 19 . . . . . . . . . . . . 10 Sept. 23 . . . . . . . . . . . . 14

Sept. 10 . . . . . . . . . . . . . . Sept. 23 . . . . . . . . . . . . 13 Oct . . . . . . . . . . . . 23

Sept. 11 . . . . . . . . . . . . . . Sept. 24 . . . . . . . . . . . . 13 Oct. . . . . . . . . . . . . 23

Sept. 12 . . . . . . . . . . . . . . Sept. 24 . . . . . . . . . . . . 12 Sept. 24 . . . . . . . . . . . . 12

Sept. 13 . . . . . . . . . . . . . . Sept. 26 . . . . . . . . . . . . 13 Oct 5 . . . . . . . . . . . . 22

Sept. 14 . . . . . . . . . . . . . . Sept. 27 . . . . . . . . . . . . 13 Oct 3 . . . . . . . . . . . . 19

Sept. 15 . . . . . . . . . . . . . . Sept. 27 . . . . . . . . . . . . 12 Oct 4 . . . . . . . . t 19

Sept. 16 . . . . . . . . . . . . . . Oct. 1g . . . . . . . . . . . . 25 Oct. 5 . . . . . . . . . . . . 19

Sept. 17 . . . . . . . . . . . . . . Sept 2 . . . . . . . . . . . . 12 Sept. 29 . . . . . . . . . . . . 12

Sept. 18 . . . . . . . . . . . . . . Oct. 6 . . . . . . . . . . . . 18 Oct. 7 . . . . . . . . . . . . 19

Sept. 19 . . . . . . . . . . . . . . Sept 30 . . . . . . . . . . . . 11 Oct. 7 . . . . . . . . . . . . 18

Sept. 20 . . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 17 Oct. 8 . . . . . . . . . . . . 18 '

Sept. 21 . . . . . . . . . . . . . . Oct 3 . . . . . . . . . . . . 12 Oct. 1 . . . . . . . . . . . . 10

Sept. 22 . . . . . . . . . . . . . . Oct 11 . . . . . . . . . . . . 19 Oct. 11 . . . . . . . . . . . . 19

Sept. 23 . . . . . . . . . . . . . . _Oct 3 . . . . . . . . . . . . 10 Oct. 1 . . . . . . . . . . . . 14

Sept. 24 . . . . . . . . . . . . . . Oct 5 . . . . . . . . . . . . 11 Oct. 14 . . . . . . . . . . . . 20

Sept. 25 . . . . . . . . . . . . . . Oct 12 . . . . . . . . . . . . 17 Oct. 12 . . . . . . . . . . . . 17

Sept. 26 . . . . . . . . . . . . . . Oct 11 . . . . . . . . . . . . 15 Oct. 10 . . . . . . . . . . . . 14

42 TEXAS AGRICULTURAL EXPERIMENT STATION.
Table 19.——Length of Life of Unmated Adults.—Continued.
l
_ Period, Period,
Emerged Male Dled Days Female Died Days
1916
Sept. 27 . . . . . . . . . . . . . . Oct. 1O . . . . . . . . . . . . 13 Oct. 15 . . . . . . . . . . . . 18

Sept. 28 . . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 9 Oct. 17 . . . . . . . . . . . . 19

Sept. 29 . . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 13 Oct. 16 . . . . . . . . . . . . 17

Sept. 3O . . . . . . . . . . . . . . Oct. 1O . . . . . . . . . . . . 1O Oct. 13 . . . . . . . . . . . . 13

Oct 1 . . . . . . . . . . . . . . Oct. 22 . . . . . . . . . . . . - 21 Oct. 2O . . . . . . . . . . .. 19

Oct 2 . . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 11 Oct. 25 . . . . . . . . . . . . 23

Oct 3 . . . . . . . . . . . . . . Oct. 14 . . . . . . . . . . . . 11 Oct. 29 . . . . . . . . . . . . 26

Oct 4 . . . . . . . . . . . . . . Oct. 14 . . . . . . . . . . . . 10 Nov. 1 . . . . . . . . . . . . 28

Oct 5 . . . . . . . . . . . . .. Oct. 22 . . . . . . . . . . .. 17 Oct 18 . . . . . . . . . . .. 13

Oct 6 . . . . . . . . . . . . . . Oct. 18 . . . . . . . . . . . . 12 Nov 3 . . . . . . . . . . . . 28

Oct 7 . . . . . . . . . . . . . . Oct. 24 . . . . . . . . . . . . 17 Nov. 5 . . . . . . . . . . . . 29

Oct 8 . . . . . . . . . . . . . . Oct. 27 . . . . . . . . . . . . 19 Oct. 31 . . . . . . . . . . . . 23

Oct 9 . . . . . . . . . . . . . . Oct. 28 . . . . . . . . . . . . 19 Nov 4 . . . . . . . . . . . . 26

Oct 10 . . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 19 Oct 28 . . . . . . . . . . . . 18

Oct 11 . . . . . . . . . . . . . . Oct. 31 . . . . . . . . . . . . 20 Nov 3 . . . . . . . . . . . . 23

Oct 12 . . . . . . . . . . . . . . Oct. 26 . . . . . . . . . . . . 14 Nov 5 . . . . . . . . . . . . 24

Oct 13 . . . . . . . . . . . . .. Nov . . . . . . . . . . . . 19 Nov 3 . . . . . . . . . . .. 21

Oct 14 . . . . . . . . . . . . . . Nov. 3 . . . . . . . . . . . . 20 Nov 2 . . . . . . . . . . . . 19

Oct 15 . . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 14 Nov 7 . . . . . . . . . . . . 23

Oct 16 . . . . . . . . . . . . . . Nov 7 . . . . . . . . . . . . 22 Nov 7 . . . . . . . . . . . . 22

Oct 17 . . . . . . . . . . . . . . Nov 6 . . . . . . . . . . . . 2O Nov 11 . . . . . . . . . . . . 25

Oct 18 . . . . . . . . . . . . .. Nov 13 . . . . . . . . . . .. 26 Nov 5 . . . . . . . . . . .. 18

Oct 19 . . . . . . . . . . . . .. Nov 5 . . . . . . . . . . .. 17 Nov 16 . . . . . . . . . . .. 28

Oct 2O . . . . . . . . . . . . . . Nov 2 . . . . . . . . . . . . 13 Nov. 6 . . . . . . . . . . . . 17

Oct 21 . . . . . . . . . . . . . . Nov 19 . . . . . . . . . . . . 29 Nov. 25 . . . . . . . . . . . . 35

Oct 22 . . . . . . . . . . . . . . Nov 6 . . . . . . . . . . . . 15 Nov 12 . . . . . . . . . . . . 21

Oct 23 . . . . . . . . . . . . .. Nov 12 . . . . . . . . . . . . 2O Nov 9 . . . . . . . . . . .. 17

Oct 24 . . . . . . . . . . . . . . Nov 9 . . . . . . . . . . . . 16 Nov 14 . . . . . . . . . . .. 21

Oct 25 . . . . . . . . . . . . .. Nov 7 . . . . . . . . . . .. 13 Nov 11 . . . . . . . . . . .. 17

Oct 26 . . . . . . . . . . . . .. Nov 7 . . . . . . . . . . . . 12 Nov. 21 . . . . . . . . . . .. 26

Oct 27 . . . . . . . . . . . . . . Nov 8 . . . . . . . . . . . . 12 Nov 2O . . . . . . . . . . . . 24

Oct 28 . . . . . . . . . . . . . . Nov 26 . . . . . . . . . . . . 29 Dec 8 . . . . . . . . . . . . 41

Oct 29 . . . . . . . . . . . . . . Nov 23 . . . . . . . . . . . . 25 Nov 16 . . . . . . . . . . . . 18

Oct 3O . . . . . . . . . . . . . . Nov 19 . . . . . . . . . . . . 2O Dec 3 . . . . . . . . . . . . 34

Oct 31 . . . . . . . . . . . . . . Nov 23 . . . . . . . . . . . . 23 Dec 9 . . . . . . . . . . . . 39

Nov 1 . . . . . . . . . . . . . . Nov 22 . . . . . . . . . . . . 21 Nov. 25 . . . . . . . . . . . . 24

Nov 2 . . . . . . . . . . . . . . Nov. 27 . . . . . . . . . . . . 25 Nov 27 . . . . . . . . . . . . 25

Nov 3 . . . . . . . . . . . . . . Dec 9 . . . . . . . . . . . . 36 Dec 1O . . . . . . . . . . . . 37

Nov 4 . . . . . . . . . . . . . . Nov 30 . . . . . . . . . . . . 26 Dec 9 . . . . . . . . . . . . 35

Nov 5 . . . . . . . . . . . . . . Dec 4 . . . . . . . . . . . . 29 Dec 15 . . . . . . . . . . . . 40

Nov 6 . . . . . . . . . . . . . . Dec 9 . . . . . . . . . . . . 33 Dec 14 . . . . . . . . . . . . 38

Nov 7 . . . . . . . . . . . . . . Dec 9 . . . . . . . . . . . . 32 Dec 1O . . . . . . . . . . . . 33

Nov 8 . . . . . . . . . . . . .. Dec 9 . . . . . . . . . . .. 31 Dec 15 . . . . . . . . . . .. 37

Nov 9 . . . . . . . . . . . . . .- Dec 8 . . . . . . . . . . . . 29 Dec 15 . . . . . . . . . . .. 36

Nov 11 . . . . . . . . . . . . . . Nov 27 . . . . . . . . . . .. 16 Dec 14 . . . . . . . . . . .. 33

Nov 12 . . . . . . . . . . . . . . Dec 15 . . . . . . . . . . . . 33 Dec 16 . . . . . . . . . . .. 34

Nov 13 . . . . . . . . . . . . .. Dec 4 . . . . . . . . . . .. 31 Jan 15 . . . . . . . . . . .. 63

Nov 18 . . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 2O Jan 16 . . . . . . . . . . . . 59

Nov 19 . . . . . . . . . . . . .. Dec 2 . . . . . . . . . . .. 13 Jan 9 . . . . . . . . . . . . 51

Nov 20 . . . . . . . . . . . . .. Jan 1 . . . . . . . . . . .. 42 Jan 15 . . . . . . . . . . .. 56

Nov 21 . . . . . . . . . . . . . . Dec 1O . . . . . . . . . . . . 2O Dec 21 . . . . . . . . . . .. 61

Nov 22 . . . . . . . . . . . . . . Dec 7 . . . . . . . . . . . . 26 Dec 14 . . . . . . . . . . . . 53

Nov 23 . . . . . . . . . . . . .. Dec. 16 . . . . . . . . . . .. 34 Jan 1 . . . . . . . . . . .. 39

Nov. 24 . . . . . . . . . . . . . . Dec 28 . . . . . . . . . . . . 5O Jan 1O . . . . . . . . . . . . 47

Nov 27 . . . . . . . . . . . . .. Jan 13 . . . . . . . . . . .. 47 Jan 10 . . . . . . . . . . .. 44

Nov 28 . . . . . . . . . . . . .. Jan 7 . . . . . . . . . . .. 40 Jan 3 . . . . . . . . . . .. 36

Nov 3O . . . . . . . . . . . . .. Jan 3 . . . . . . . . . . .. 34 Jan. 8 . . . . . . . . . . . . 39

Dec 1 . . . . . . . . . . . . . . Dec 25 . . . . . . . . . . . . 24 Dec. 29 . . . . . . . . . . . . 28

Dec 2 . . . . . . . . . . . . . . Jan 3 . . . . . . . . . . . . 32 Jan. 1O . . . . . . . . . . . . 39

Dec 3 . . . . . . . . . . . . .. Jan 15 . . . . . . . . . . .. 43 Jan. 13 . . . . . . . . . . .. 41

Dec 4 . . . . . . . . . . . . .. Jan 7 . . . . . . . . . . .. 34 Jan. 28 . . . . . . . . . . .. 55

Dec 5 . . . . . . . . . . . . .. Jan. 24 . . . . . . . . . . .. 37 Jan. 16 . . . .  42

Dec 6 . . . . . . . . . . . . . . Feb 6 . . . . . . . . . . . . 62 Jan. 15 . . . . . . . . . . . . 40

Dec 7 . . . . . . . . . . . . . . Jan 14 . . . . . . . . . . . . 38 Jan. 14 . . . . . . . . . . . . 38

Dec 8 . . . . . . . . . . . . .. Jan 21 . . . . . . . . . . . . 44 Jan. 3O . . . . . . . . . . .. 53

Dec 10 . . . . . . . . . . . . . . Jan 24 . . . . . . . . . . . . 45 Jan. 26 . . . . . . . . . . . . 47

Dec 11 . . . . . . . . . . . . .. Jan 30 . . . . . . . . . . .. 50 Jan. 16 . . . . . . . . . . .. 36

Dec 13 . . . . . . . . . . . . . . Feb 17 . . . . . . . . . . . . 66 Jan. 15 . . . . . . . . . . . . 33

Dec 14 . . . . . . . . . . . . . . Feb 22 . . . . . . . . . . . . 7O Jan 23 . . . . . . . . . . . .. 4O

Dec 17 . . . . . . . . . . . . . . Jan 28 . . . . . . . . . . . . 42 Jan. 23 . . . . . . . . . . . . 37

Dec 18 . . . . . . . . . . . . .. Jan. 28 . . . . . . . . . . .. 41 Jan 28 . . . . . . . . . . .. 41

Dec 19 . . . . . . . . . . . . .. Feb. 8 . . . . . . . . . . .. 51 Jan 19 . . . . . . . . . . . ._ 31

Dec 2O . . . . . . . . . . . . . . Feb 19 . . . . . . . . . . . . 3O Feb. 6 . . . . . . . . . . . . 48

Dec 21 . . . . . . . . . . . . . . Feb. 6 . . . . . . . . . . . . 47 Feb. 8 . . . . . . . . . . . . 49

Dec 24 . . . . . . . . . . . . . . Feb 21 . . . . . . . . . . . . 59 Feb 23 . . . . . . . . . . . . 61

Dec. 25 . . . . . . . . . . . . . . Feb 14 . . . . . . . . . . . . 51 Feb. 4 . . . . . . . . . . . . 51

Dec. 26 . . . . . . . . . . . . . . Feb. 6 . . . . . . . . . . . . . 42 Feb. 26 . . . . . . . . . . . . 62

Dec. 27 . . . . . . . . . . . . .. Feb 18 . . . . . . . . . . .. 53 Feb. 21 . . . . . . . . . . .. 56

Dec. 28, . . . . . . . . . . . . . 19 . . . . . . . . . . . . 53 Feb. 11 . . . . . . . . . . . . 45

THE COWPEA WVEEVIL.

Table l9.—Length of Life of Unmated Adults.—Continued.

43

Period, Period,
Emerged Male Died Days Female Died Days
1916
Dec. 29 . . . . . . . . . . . . . . Feb. 18 . . . . . . . . . . . . 57 Feb. 11 . . . . . . . . . . . . 44

Dec. 31 . . . . . . . . . . . . . . Feb. 22 . . . . . . . . . . . . 53 Feb. 23 . . . . . . . . . . . . 54

48 Feb. 23 . . . . . . . . . . .. 53

55 Feb. 11 . . . . . . . . . . . . 40

50 Feb. I8 . . . . . . . . . . . . 46

50 Feb. 25 . . . . . . . . . . .. 52

47 Feb. 22 . . . . . . . . . . .. 48

45 Feb. 25 . . . . . . . . . . .. 49

48 Feb. 27 . . . . . . . . . . .. 49

46 Mar. 15 . . . . . . . . . . . . 64

46 Mar. 21 . . . . . . . . . . . . 69

31 Mar. 7 . . . . . . . . . . . . 46

46 Mar. 6 . . . . . . . . . . . . 44

43 Mar. 15 . . . . . . . . . . . . 52

38 ar. . . . . . . . . . . . . 60

45 Mar. 21 . . . . . . . . . . . . 51

41 Mar. 3O . . . . . . . . . . . . 59

28 Mar. 22 . . . . . . . . . . . . 58

21 Mar. 9 . . . . . . . . . . . . 32

51 April 4 . . . . . . . . . . . . 55

38 Mar. 2 . . . . . . . . . . . . 39

34 Mar. 23 . . . . . . . . . . . . 40

34 Mar. 12 . . . . . . . . . . . . 28

31 Mar 27 . . . . . . . . . . .. 42

30 Mar 24 . . . . . . . . . . .. 38

29 Mar 17 . . . . . . . . . . . . 30

3O Mar 17 . . . . . . . . . . . . 29

41 April 6 . . . . . . . . . . . . 48

35 April 4 . . . . . . . . . . .. 45

29 Mar. 26 . . . . . . . . . . . . 35

39 April 5 . . . . . . . . . . . . 44

28 April . . . . . . . . . . . . 44

27 Mar. 3 . . . . . . . . . . . . 36

29 Mar. 28 . . . . . . . . . . . . 33

28 April 4 . . . . . . . . . . . . 39

35 April 12 . . . . . . . . . . . . 46

27 April 3 . . . . . . . . . . . . 36

36 April 12 . . . . . . . . . . . . 44

22 April 14 . . . . . . . . . . . . 45

13 Mar. . . . . . . . . . . . . 15

18 Mar. 23 . . . . . . . . . . . . 19

34 Mar. , . . . . . . . . . . . 21

3O April 23 . . . . . . . . . . . . 16

22 April . . . . . . . . . . . . 25

31 April 16 . . . . . . . . . . . . 38

27 April 22 . . . . . . . . . . . . 43

10 April . . . . . . . . . . . . 27'

42 April 23 . . . . . . . . . . . . 42

23 April 25 . . . . . . . . . . . . 43

28 April . . . . . . . . . . . . 28

31 April 22 . . . . . . . . . . . . 38

26 April 16 . . . . . . . . . . . . 31

20 April . . . . . . . . . . . . 3O

26 April 28 . . . . . . . . . . . . 41

24 April 19 . . . . . . . . . . . . 31

33 April 16 . . . . . . . . . . . . 27

21 April 29 . . . . . . . . . . . . 39

24 April 14 . . . . . . . . . . . . 23

19 April . . . . . . . . . . . . 35

18 April . . . . . . . . . . . . 15

25 April 28 . . . . . . . . . . . . 34

29 May . . . . . . . . . . . . 37

27 May . . . . . . . . . . . . 35

27 April 26 . . . . . . . . . . . . 29

22 April 24 . . . . . . . . . . . . 26

24 April 24 . . . . . . . . . . . . 25

18 April 20 . . . . . . . . . . . . 20

27 April 29 . . . . . . . . . . . . 28

26 ay . . . . . . . . . . . . 29

25 April 28 . . . . . . . . . . . . 25

29 May . . . . . . . . . . . . 44

3O May . . . . . . . . . . . . 31

25 May 14 . . . . . . . . . . . . 38

_ ay 27 May . . . . . . . . . . . . 30

April 8 . . . . . . . . . . . . . . April 28 . . . . . . . . . . . . 2O April 29 . . . . . . . . . . . . 21

April 9 . . . . . . . . . . . . . . April 30 . . . . . . . . . . . . 21 May . . . . . . . . . . . . 32

April 10 . . . . . . . . . . . . .. May 10 . . . . . . . . . . . . 3O May 11 . . . . . . . . . . .. 31

41 TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 19.—Length of Life of Unmated Adults.-—Continued.

at flbhnvlbv‘. Anam- .1 A, 

_ Period, _ Period, Tj

Emerged Male Died Days Female_D1ed Days 

*~s

i

April 11 . . . . . . . . . . . . . . April 3O . . . . . . . . . . . . 19 May 4 . . . . . . . . . . . . 23 A

April 12 . . . . . . . . . . . . . . May 6 . . . . . . . . . . . . 24 May 15 . . . . . . . . . . .. 33 5

April 13 . . . . . . . . . . . . . . May 5 . . . . . . . . . . . . 22 April 29 . . . . . . . . . . . . 12

April 14 . . . . . . . . . . . . . . May 2 . . . . . . . . . . . . 18 May 19 . . . . . . . . . . . . 35

April 15 . . . . . . . . . . . . .. May 5 . . . . . . . . . . .. 20 May 24 . . . . . . . . . . .. 39

ipril  . . . . . . . . . . . . .. May L11 . . . . . . . . . . ..  lfiay 1g . . . . . . . . . . .. » 

pr1 . . . . . . . . . . . . . . ay . . . . . . . . . . . . ay . . . . . . . . . . . .

April 18. . . . .1 . . . . . . . .. May ,1 5 . . . . . . . . . . .. 17 May 11 . . . . . . . . . . .. 23

April 19 . . . . . . . . . . . . .. May 4 . . . . . . . . . . .. 15 May 11 . . . . . . . . . . .. 22

April 20 . . . . . . . . . . . . . . May 10 . . . . . . . . . . . . 20 May 16 . . . . . . . . . . . . 26

April 21 . . . . . . . . . . . . . . May 7 . . . . . . . . . . . . 16 May 18 . . . . . . . . . . . . 27

April 22 . . . . . . . . . . . . . . May 10 . . . . . . . . . . . . 18 May 14 . . . . . . . . . . . . 22

April 23 . . . . . . . . . . . . .. May 12 . . . . . . . . . . .. 19 May 11 . . . . . . . . . . .. 18

April 24 . . . . . . . . . . . . .. May 10 . . . . . . . . . . .. 16 _ May 19 . . . . . . . . . . .. 25

April 25 . . . . . . . . . . . . . . May 14 . . . . . . . . . . . . 19 May 21 . . . . . . . . . . . . 26

April 26 . . . . . . . . . . . . .. May 13 . . . . . . . . . . .. 17 May 25. . ., . . . . . . . .. 29

April 27 . . . . . . . . . . . . . . May 13 . . . . . . . . . . . 16 May 24 . . . . . . . . . . . . 27

Apr1l28 . . . . . . . . . . . . . . May 15 . . . . . . . . . . . . 17 May 22 . . . . . . . . . . . . 24

pr1l29 . . . . . . . . . . . . .. May 17 . . . . . . . . . . .. 18 May 15 . . . . . . . . . . .. 16

A r1130 . . . . . . . . . . . . .. May 12 . . . . . . . . . . .. 12 May 24 . . . . . . . . . . .. 24

Ngy 52 . . . . . . . . . . . . .. June 15 . . . . . . . . . . .. 44 June 19 . . . . . . . . . . .. 48

May -'-_3 . . . . . . . . . . . . .. June 13 . . . . . . . . . . . . 41 June 14 . . . . . . . . . . .. 42

May g4 . . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 40 June 14 . . . . . . . . . . .. 41

May [5 . . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 39 June 16 . . . . . . . . . . .. 42

ay L6 . . . . . . . . . . . . . . June 18 . . . . . . . . . . .. 43 June 21 . . . . . . . . . . .. 46

May - 7 . . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 37 June 18 . . . . . . . . . . .. 41

ay . . . . . . . . . . . . .. June 15 . . . . . . . . . . .. 37 June 19 . . . . . . . . . . .. 41

ay 10 . . . . . . . . . . . . .. June 18 . . . . . . . . . . .. 39 June 21 . . . . . . . . . . .. 42

May 11 . . . . . . . . . . . . . . June 2O . . . . . . . . . . . . 4O June 22 . . . . . . . . . . .. 42

May 12 . . . . . . . . . . . . .. June 21 . . . . . . . . . . . . 40 June 22 . . . . . . . . . . .. 41

ay 13 . . . . . . . . . . . . . . June 23 . . . . . . . . . . .. 41 June 20 . . . . . . . . . . .. 38

ALI/gay  . . . . . . . . . . . . . . June  . . . . . . . . . . . .  June  . . . . . . . . . . . . 

ay . . . . . . . . . . . . . . une . . . . . . . . . . . . une . . . . . . . . . . . .

ay 6 . . . . . . . . . . . . . . June 22 . . . . . . . . . . . . 37 June 27 . . . . . . . . . . . . 42

May  . . . . . . . . . . . . . . June  . . . . . . . . . . ..  gulne 3O . . . . . . . . . . .. 

ay . . . . . . . . . . . . . . une . . . . . . . . . . . . u y . . . . . . . . . . . .

May 19 . . . . . . . . . . . . .. June 27 . . . . . . . . . . .. 39 July 4 . . . . . . . . . . . . 46

ay 21 . . . . . . . . . . . . . . June 29 . . . . . . . . . . .. 39 June 3O . . . . . . . . . . .. 1O

May 22 . . . . . . . . . . . . . . une 29 . . . . . . . . . . . . 38 July 6 . . . . . . . . . . . . 45

May 23 . . . . . . . . . . . . . . June 23 . . . . . . . . . . . . 31 July 6 . . . . . . . . . . . . 44

May 24 . . . . . . . . . . . . .. y 2 . . . . . . . . . . . . 39 July 1 . . . . . . . . . . .. 38

May 25 . . . . . . . . . . . . . . July 10 . . . . . . . . . . . . 46 July 13 . . . . . . . . . . . . 49

May 26 . . . . . . . . . . . . . . July . . . . . . . . . . . . 42 July . . . . . . . . . . . . 38

May 27 . . . . . . . . . . . . .. July 11 . . . . . . . . . . .. 45 July 15 . . . . . . . . . . .. 49

May 28 . . . . . . . . . . . . . . July 12 . . . . . . . . . . . . 45 July 16 . . . . . . . . . . .. 49

May 29 . . . . . . . . . . . . .. July 13 . . . . . . . . . . . . 45 July 19 . . . . . . . . . . . . 51

ay 30 . . . . . . . . . . . . .. July 17 . . . . . . . . . . .. 48 July 19 . . . . . . . . . . . . 50

May 31 . . . . . . . . . . . . .. July 14 . . . . . . . . . . .. 44 July 18 . . . . . . . . . . . . 48

Length of Life of Muted Adults.

The notes recorded in Table 2O were made in order to establish the
total length of life of both sexes of mated weevils, and definitely deter-
mine the length of the period over which they remain destructive to
the cowpea. These notes were begun in September, 1915, continued
throughout the year 1916, and January and February of 1917. It
will be noted that the average length of life throughout the warm
months is much shorter than for the colder months. A total of 5 or 6
days for the life period of each sex occurred frequently during July,
August, and September, While the period extends from 30 to 40 days
during December and January. The shortest period for the male was
3 days, from June 23 to June 26, 1916; for the female, 4 days, from
October 31 to November 4, 1915. The longest period for the male was
40 days, from January 9 to February 18, 191'?‘ ; for the female, 50 days,
from January 13 to March 4, 1917.

THE CowPEA WEEVIL.

Table 20.—Length of Life of Mated Adults.

_ Period, Period,
Emerged Male Died Days Female Died Days
1915
Sept. 9 . . . . . . . . . . . . . . Sept. 16 . . . . . . . . . . . . 7 Sept. 15 . . . . . . . . . . . . 6

Sept 9 . . . . . . . . . . . . . . Sept. 17 . . . . . . . . . . . . 8 Sept. 17 . . . . . . . . . . . . 8

Sept 9 . . . . . . . . . . . . . . Sept. 17 . . . . . . . . . . . . 8 Sept. 16 . . . . . . . . . . . . 7

Sept 9 . . . . . . . . . . . . . . Sept. 18 . . . . . . . . . . . . 9 Sept. 17 . . . . . . . . . . . . 8

Sept 12 . . . . . . . . . . . . . . Sept. 19 . . . . . . . . . . .  7 Sept. 19 . . . . . . . . . . . . 7

Sept. 14 . . . . . . . . . . . . . . Sept. 21 . . . . . . . . . . . . 7 Sept. 2O . . . . . . . . . . . . 6

Sept. 15 . . . . . . . . . . . . . . Sept. 23 . . . . . . . . . . . . 8 Oct. 5 . . . . . . . . . . . . 2O

Sept. 15 . . . . . . . . . . . . . . Sept. 21 . . . . . . . . . . . . 6 Oct. 1 . . . . . . . . . . . . 16

Sept. 15 . . . . . . . . . . . . . . Sept. 24 . . . . . . . . . . . . 9 Sept. 24 . . . . . . . . . . . . 39

Sept. 21 . . . . . . . . . . . . . . Sept. 26 . . . . . . . . . . . . 5 Octn 1 . . . . . . . . . . . . . 10

Sept. 21 . . . . . . . . . . . . . . Oct. 4 . . . . . . . . . . . . 13 Oct. 4 . . . . . . . . . . . . 13

Sept 21 . . . . . . . . . . . . . . Sept 28 . . . . . . . . . . . . 7 Sept. 28 . . . . . . . . . . . . 7

Sept 29 . . . . . . . . . . . . . . Oct. 10 . . . . . . . . . . .. 11 Oct. 11 . . . . . . . . . . . . 12

Oct. 5 . . . . . . . . . . . . .. Oct. 17 . . . . . . . . . . .. 12 Oct. 17 . . . . . . . . . . .. 12

Oct. 5 . . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 8 Oct. 13 . . . . . . . . . . . . 8

Oct. 13 . . . . . . . . . . . . . . Oct. 25 . . . . . . . . . . . . 12 Oct. 25 . . . . . . . . . . . . 12

Oct. 13 . . . . . . . . . . . . .. Oct. 24 . . . . . . . . . . .. 11 Oct. 24 . . . . . . . . . . .. 11

Oct. 14 . . . . . . . . . . . . .. Oct. 25 . . . . . . . . . . . . 11 Oct. 26 . . . . . . . . . . .. 12

Oct. 16 . . . . . . . . . . . . . . Oct. 24 . . . . . . . . . . . . 8 Oct. 25 . . . . . . . . . . . . 9

Oct. 17 . . . . . . . . . . . . .. Oct. 29 . . . . . . . . . . .. 12 Oct. 3O . . . . . . . . . . .. 13

Oct. 18 . . . . . . . . . . . . . . Oct. 3O . . . . . . . . . . . . 12 Nov. 5 . . . . . . . . . . . . 18

Oct. 2O . . . . . . . . . . . . .. Oct. 30 . . . . . . . . . . .. 10 Oct. 29 . . . . . . . . . . .. 9

Oct. 22 . . . . . . . . . . . . .. Nov. 2 . . . . . . . . . . . . 11 Nov. 7 . . . . . . . . . . .. 16

Oct. 22 . . . . . . . . . . . . . .. Nov. 3 . . . . . . . . . . . . 12 Nov. 3 . . . . . . . . . . .. 1.6

Oct. 23 . . . . . . . . . . . . .. Nov. 7 . . . . . . . . . . .. 15 Nov. 7 . . . . . . . . . . .. 16

Oct. 24 . . . . . . . . . . . . . . Nov. 3 . . . . . . . . . . . . 1O Nov. 8 . . . . . . . . . . . . 9

Oct. 25 . . . . . . . . . . . . . . Nov. 2 . . . . . . . . . . . . 8 Nov. 7 . . . . . . . . . . . . 9

Oct. 26 . . . . . . . . . . . . . . Nov. 7 . . . . . . . . . . . . 12 Nov. 3 . . . . . . . . . . . . 12

Oct. 27 . . . . . . . . . . . . . . Nov. 9 . . . . . . . . . . .. 13 Nov. 7 . . . . . . . . . . . . 15

Oct. 28 . . . . . . . . . . . . .. Nov. 9 . . . . . . . . . . .. 12 Nov. 11 . . . . . . . . . . .. 12

Oct. 3O . . . . . . . . . . . . . . Nov. 8 . . . . . . . . . . . . 1O Nov. 8 . . . . . . . . . . . . 5

Oct. 31 . . . . . . . . . . . . . . Nov. 8 . . . . . . . . . . . . 9 Nov. 4 . . . . . . . . . . . . 4

Nov. 1 . . . . . . . . . . . . .. Nov. 10 . . . .  9 Nov. 14 . . . . . . . . . . .. 13

Nov 2 . . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 19 Nov. 16 . . . . . . . . . . . . 14

Nov 5 . . . . . . . . . . . . .. Nov 17 . . . . . . . . . . .. 12 Nov. 22 . . . . . . . . . . .. 17

Nov 6 . . . . . . . . . . . . .. Nov. 10 . . . . . . . . . . .. 4 Nov.11 . . . . . . . . . . .. 5

Nov 8 . . . . . . . . . . . . .. Nov. 21 . . . . . . . . . . .. 13 Nov. 21 . . . . . . . . . . .. 13

Nov 8 . . . . . . . . . . . . .. Nov. 22 . . . . . . . . . . .. 14 Nov. 22 . . . . . . . . . . . . 14

Nov 9 . . . . . . . . . . . . .. Nov. 22 . . . . . . . . . . .. 13 Nov. 23 . . . . . . . . . . . . 14

Nov 10 . . . . . . . . . . . . .. -Nov 21 . . . . . . . . . . .. 11 Nov. 21 . . . . . . . . . . .. 11

Nov 11 . . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 1O Nov. 23 . . . . . . . . . . .. 12

Nov 12 . . . . . . . . . . . . .. Nov 22 . . . . . . . . . . .. 10 Nov. 22 . . . . . . . . . . . . 1O

Nov 13 . . . . . . . . . . . . .. Nov 22 . . . . . . . . . . .. 9 Nov. 23 . . . . . . . . . . . . 1O

Nov 14 . . . . . . . . . . . . .. Nov 22 . . . . . . . . . . . . 8 Nov. 22 . . . . . . . . . . . . 8

Nov 15 . . . . . . . . . . . . . . Nov 25 . . . . . . . . . . .. 1O Nov. 25- . . . . . . . . . . . 10

Nov 16 . . . . . . . . . . . . .. Nov 22 . . . . . . . . . . .. 1O Nov. 22 . . . . . . . . . . . . 6

Nov 17 . . . . . . . . . . . . .. Nov 26 . . . . . . . . . . .. 9 Nov. 27 . . . . . . . . . . .. 10

Nov 18 . . . . . . . . . . . . .. Nov 28 . . . . . . . . . . .. 1O Nov. 29 . . . . . . . . . . .. 11

Nov 19 . . . . . . . . . . . . .. Nov 29 . . . . . . . . . . .. 10 Nov. 29 . . . . . . . . . . .. 1O

Nov 2O . . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 8 Nov. 30 . . . . . . . . . . . . 1O

Nov 21 . . . . . . . . . . . . .. Nov. 3O . . . . . . . . . . .. 9 Dec. 3 . . . . . . . . . . .. 12

Nov 22 . . . . . . . . . . . . . . Nov. 29 . . . . . . . . . . . . 7 Dec. 1 . . . . . . . . . . . . 9

Nov 23 . . . . . . . . . . . . . . Nov 3O . . . . . . . . . . . . 7 Dec. 2 . . . . . . . . . . . . 9

Nov 24 . . . . . . . . . . . . . . Dec. 2 . . . . . . . . . . . . 8 Dec. 3 . . . . . . . . . . . . 9

Nov. 25 . . . . . . . . . . . . . . Dec. 4 . . . . . . . . . . .. 9 Dec. 5 . . . . . . . . . . . . 10

Nov. 26 . . . . . . . . . . . . . . Dec. 4 . . . . . . . . . . . . 8 Dec. 8 . . . . . . . . . . . . 12

Nov. 27 . . . . . . . . . . . . . . Dec. 7 . . . . . . . . . . . . 1O Dec. 7 . . . . . . . . . . . . 10

Nov. 28 . . . . . . . . . . . . . . Dec. 5 . . . . . . . . . . . . 7 Dec. 8 . . . . . . . . . . . . 1O

Nov. 29 . . . . . . . . . . . . .. Dec. 2O . . . . . . . . . . . . 21 Dec. 7 . . . . . . . . . . . . 8

Nov 3O . . . . . . . . . . . . . . Dec. 1O . . . . . . . . . . .. 1O Dec. 12 . . . . . . . . . . .. 12

Dec 1 . . . . . . . . . . . . . . Dec. 11 . . . . . . . . . . .. 1O Dec. 12 . . . . . . . . . . .. 11

Dec 2 . . . . . . . . . . . . . . Dec. 15 . . . . . . . . . . . . 13 Dec. 22 . . . . . . . . . . . . 20

Dec 3 . . . . . . . . . . . . . . Dec. 26 . . . . . . . . . . .. 23 Dec. 29 . . . . . . . . . . .. 26

Dec 4 . . . . . . . . . . . . . . Dec. 27 . . . . . . . . . . . . 23 Jan. . . . . . . . . . . . . 31

Dec 5 . . . . . . . . . . . . . . Jan. 4 . . . . . . . . . . . . 3O Dec. 24

Dec 6 . . . . . . . . . . . . . . Jan. 2 . . . . . . . . . . . . 27 Jan. 27

Dec 7 . . . . . . . . . . . . . . Jan 3 . . . . . . . . . . . . 27 Jan. 33

Dec 8 . . . . . . . . . . . . . . Jan 3 . . . . . . . . . . . . 26 Jan. 37

Dec 9 . . . . . . . . . . . . .. Jan. 7 . . . . . . . . . . .. 29 Jan. 36

Dec 1O . . . . . . . . . . . . . . Jan 11 . . . . . . . . . . . . 32 Jan. 32

Dec 11 . . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 31 Jan. 31

Dec 12 . . . . . . . . . . . . . . Dec 25 . . . . . . . . . . . . 13 Jan. 3O

Dec 13 . . . . . . . . . . . . .. Jan 9 . . - . . . . . . . . . . 27 Jan. 29

Dec 14 . . . . . . . . . . . . . . Jan 9 . . . . . . . . . . . . 26 Jan. 28

Dec 15 . . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 27 Jan 27

Dec 16 . . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 26 Jan 26

Dec 17 . . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 25 Jan 33

Dec 19 . . . . . . . . . . . . .. Jan 19 . . . . . . . . . . .. 31 Jan 16

Dec 21 . . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . .. 21 Jan. 19

 

4. 1- TEXAS AGRICULTURAL EXPERIMENT STATION.
Table 20. Length of Life of Mated Adults-——Continued.
_ Period, _ Period,
Emerged Male Died Days Female Died Days
24 Jan. 15 . . . . . . . . . . .. 24

21 Jan. 15 . . . . . . . . . . . . 21

14 Jan. 9 . . . . . . . . . . . . 14

17 Jan. 15 . . . . . . . . . .-. 17

13 Jan. 18 . . . . . . . . . . . . 16

12 Jan 22 . . . . . . . . . . . . 12

8 Jan 24 . . . . . . . . . . . . 8

6 Jan 24 . . . . . . . . . . . . 6

33 Feb 21 . . . . . . . . . . . . 33

28 Mar 8 . . . . . . . . . . . . 37

34 Jan 27 . . . . . . . . . . . . 34

29 Mar 8 . . . . . . . . . . . . 39

16 Mar 8 . . . . . . . . . . . . 29

23 Mar 8 . . . . . . . . . . . . 23

2O Mar. 2O . . . . . . . . . . . . 16

12 Mar. 21 . . . . . . . . . . . . 16

16 Mar. 21 . . . . . . . . . . . . 16

18 Mar. 24 . . . . . . . . . . . . 18

25 Mar. 21 . . . . . . . . . . . . 13

23 April 12 . . . . . . . . . . . . 18

17 April 13 . . . . . . . . . . . . 26

25 April 4 . . . . . . . . . . . . 16

22 April 5 . . . . . . . . . . . . 15

26 April 10 . . . . . . . . . . . . 19

39 Mar. 31 . . . . . . . . . . . . 6

2O April 25 . . . . . . . . . . . . 29

15 April 16 . . . . . . . . . . . . 19

21 April 18 . . . . . . . . . . . . 19

24 April 18 . . . . . . . . . . . . 16

15 April 23 . . . . . . . . . . . . 18

17 April 2O . . . . . . . . . . . . 14

9 April . . . . . . . . . . . . 14

13 April 24 .\ . . . . . . . 14

12 April 24 . . . . . . . . . . . . 13

11 April 24 . . . . . . . . . . . . 12

17 April 23 . . . . . . . . . . . . 1O

8 April 24 . . . . . . . . . . . . 9

11 ay . . . . . . . . . . . . 17

17 April 30 . . . . . . . . . . . . 13

13 ay . . . . . . . . . . . . 17

14' May 1O . . . . . . . . . . . . 21

15 May 3 . . . . . . . . . . . . <13

14 May 7 . . . . . . . . . . . . 15

7 May 8 . . . . . . . . . . . . 15

15 May 9 . . . . . . . . . . . . 15

9 May 16 . . . . . . . . . . . . 21

11 May 7 . . . .  11

11 May 9 . . . . . . . . . . . . 12

9 May 11 . . . . . . . . . . . . 11

8 May 11 . . . . . . . . . . . . 1O

11 May 16 . . . . . . . . . . . . 13

8 May 14 . . . . . . . . . . .. 1O

1O May 18 . . . . . . . . . . .. 12

1O May 18 . . . . . . . . . . . . 11

13 May 25 . . . . . . . . . . . . 17

12 May 23 . . . . . . . . . . . . 13

11 May 22 . . . . . . . . . . . . 11

8 May 29 . . . . . . . . . . . . 16

15 ay 17 . . . . . . . . . . .. 13

11 May 26 . . . . . . . . . . . . 11

12 May 26 . . . . . . . . . . . . 1O

1O May 25 . . . . . . . . . . . . 8

10 May 29 . . . . . . . . . . . . 11

9 May 3O . . . . . . . . . . . . 1O

8 June 1 . . . . . . . . . . . . 11

8 May 29 . . . . . . . . . . . . 7

9 May 30 . . . . . . . . . . . . 7

ay 24 . . . . . . . . . . . . .. June 4 . . . . . . . . . . .. 11 June 3 . . . . . . . . . . .. 1O

May 25 . . . . . . . . . . . . .. June 3 . . . . . . . . . . .. 9 June 4 . . . . . . . . . . . . 1O

May 27 . . . . . . . . . . . . .. June 5 . . . . . . . . . . .. 9 June 9 . . . . . . . . . . .. 13

ay 28 . . . . . . . . . . . . .. June 6 . . . . . . . . . . .. 9 June 6 . . . . . . . . . . .. 9

May 3O . . . . . . . . . . . . .. June 7 . . . . . . . . . . .. 8 June 4 . . . . . . . . . . .. 5

May 31 . . . . . . . . . . . . . . June 14 . . . . . . . . . . .. 13 June 7 . . . . . . . . . . .. 6

June 1 . . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 10 June 11 . . . . . . . . . . .. 1O

June 3 . . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 8 June 13 . . . . . . . . . . .. 1O

June 3 . . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 8 June 12 . . . . . . . . . . .. 9

June 4 . . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 9 June 14 . . . . . . . . . . .. 1O

THE GOWPEA WEEVIL.

v Table 20.—Length of Life of Mated Adults.—Continued.

~17

Emerged

Male Died

Period,
I)ays

Female Died

Period,
I)ays

June

June 1

June
June
June
June
June

June 2

June

p-A

p-A

U)

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mmwowqowwmmomwwowmwwmqwaqwmwmmwqmwmammomumqwwmmwwou~qwqwmmwmmmm<

v-n-l rd
Or-WDUIOQOQON

June 15 . . . . . . . . . . ..

June 17 . . . . . . . . . . ..

June 16 . . . . . . . . . . ..

June 17 . . . . . . . . . . ..

June . . . . . . . . . . ..

June 20 . . . . . . . . . . ..

June 23 . . . . . . . . . . ..

June 22 . . . . . .u...u

June 24 . . . . . . . . . . ..

June 26 . . . . . . . . . . ..

June 27 . . . . . . . . . . ..

June 26 . . . . . . . . . . ..

Sept.21 . . . . . . . . . . ..

I-li-l

)-l

i-li-l

omwommmzwwmmwmwgzwwwmooqwwwmommwwwo

p-a

l-l

i-lb-l

r-H-A r-l HM
O0OOQONJQDOOOQOOOOOQDr-HdOOOOwOOOOtOOOOOQOOQ

4-8 ~ TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 20.-—Length of Life of Mated Adults.—Continued.

_ _ Period, Period,
Emerged Male Dled Days Female Died Days
11 Sept. 19 . . . . . . . . . . . . 12

10 Sept. 17 . . . . . . . . . . . .

9 Sept. 25 . . . . . . . . . . . . 16

10 Sept. 20 . . . . . . . . . . . . 10

9 Sept. 22 . . . . . . . . . . . . 11

8 Sept. 22 . . . . . . . . . . . . 10

9 Sept. 26 . . . . . . . . . . . . 13

10 Sept. 25 . . . . . . . . . . . . 11

10 Sept. 24 . . . . . . . . . . . . 9

11 Oct. . . . . . . . . . . . . 22

9 Sept. 27 . . . . . . . . . . . . 10

11 Oct. 26 . . . . . . . . . . . . 38

8 Oct. 3 . . . . . . . . . . . . 13

11 Sept. 30 . . . . . . . . . . . . 9

10 Oct. . . . . . . . . . . . . 13

11 Oct. 7 . . . . . . . . . . . . 14

Oct. 7 . . . . . . . . . . . . 13

12 Oct. 6 . . . . . . . . . . . . 11

12 Oct. 7 . . . . . . . . . . . . 11

11 Oct. 9 . . . . . . . . . . . . 12

11 Oct. . . . . . . . . . . . . 11

7 Oct. 11 . . . . . . . . . . . . 12

8 Oct. 22 . . . . . . . . . . . . 22

7 Oct. 12 . . . . . . . . . . . . 11

1O Oct. 11 . . . . . . . . . . . .

11 Oct. 14 . . . . . . . . . . . . 11

10 Oct. 14 . . . . . . . . . . . . 10

10 Oct. 16 . . . . . . . . . . . . 11

10 Oct. 16 . . . . . . . . . . . . 10

1O Oct. 17 . . . . . . . . . . . . 1O

11 Oct. 24 . . . . . . . . . . .. 16

10 Oct. 23 . . . . . . . . . . . . 14

12 Oct. 21 . . . . . . . . . . . . 11

13 Oct. 25 . . . . . . . . . . . . 14

12 Oct. 27 . . . . . . . . . . . . 15

12 Oct. 27 . . . . . . . . . . . . 14

15 Nov. . . . . . . . . . . . . 19

13 Nov. 2 . . . . . . . . . . . . 18

14 Oct. 31 . . . . . . . . . . . . 15

12 Nov. 2 . . . . . . . . . . . . 16

13 Nov. 2 . . . . . . . . . . . . 15

11 Nov. 4 . . . . . . . . . . . . 16

13 Nov. 5 . . . . . . . . . . . . 16

12 Nov. 5 . . . . . . . . . . . . 15

15 Nov. 5 . . . . . . . . . . . . 14

13 Nov. . . . . . . . . . . . . 16

Nov. 11 . . . . . . . . . . . . 18

12 Nov. 8 . . . . . . . . . . . . 14

14 Nov. 6 . . . . . . . . . . . . 11

25 Nov. 8 . . . . . . . . . . . . 12

13 Nov. 10 . . . . . . . . . . . . 13

16 Nov. 18 . . . . . . . . . . . . 20

15 Nov. 13 . . . . . . . . . . . . 14

21 Nov. 20 . . . . . . . . . . . . 20

20 Nov. 21 . . . . . . . . . . . . 20

19 Nov. 21 . . . . . . . . . . . . 19

17 Nov. 22 . . . . . . . . . . . . 19

19 Nov. 25 . . . . . . . . . . . . 21

23 Nov. 23 . . . . . . . . . . . . 18

25 Dec. 3 . . . . . . . . . . . . 27

26 Dec. 4 . . . . . . . . . . . . 27

23 Nov. 29 . . . . . . . . . . . . 23

22 Dec. . . . . . . . . . . . . 23

21 Dec. 2 . . . . . . . . . . . . 21

19 Dec. 2 . . . . . . . . . . . . 20

16 Dec. 5 . . . . . . . . . . . . 18

2O Dec. 7 . . . . . . . . . . . . 19

17 Dec. 6 . . . . . . . . . . . . 17

18 Dec. 9 . . . . . . . . . . . . 19

23 Dec. 7 . . . . . . . . . . . . 16

15 Dec. . . . . . . . . . . . . 17

18 Dec. 12 . . . . . . . . . . .. 19

13 Dec. 12 . . . . . . . . . . .. 16

14 Dec. 11 . . . . . . . . . . .. 14

2O Dec. 23 . . . . . . . . . . . . 24

15 Dec. 19 . . . . . . . . . . . . 19

27 Dec. 24 . . . . . . . . . . .. 23

13 Dec. 19 . . . . . . . . . . . . 17

24 Jan. 6 . . . . . . . . . . . . 34

THE COWPEA 1217111211111. 49

Table 20.—-Length of Life of Mated Adults.—Continued.

' Period Period,
Emerged Male Died Days Female Died Days
1916
Dec. . . . . . . . . . . . . . . Dec 3O . . . . . . . . . . . . 26 Dec. 30 . . . . . . . . . . . . 26

Dec. 5 . . . . . . . . . . . . . . Jan 4 . . . . . . . . . . . . 30 Jan 8 . . . . . . . . . . . . 34

gee (75 . . . . . . . . . . . . . . flan g . . . . . . . . . . . .  gan 2 . . . . . . . . . . . . 

t ec . . . . . . . . . . . . . . an . . . . . . . . . . . . an . . . . . . . . . . . .

‘Dec 8 . . . . . . . . . . . . . . Jan. 1O . . . . . . . . . . . . 33 Jan 9 . . . . . . . . . . . . 33

iDec . . . . . . . . . . . . . . Jan. 3 . . . . . . . . . . . . 25 Jan . . . . . . . . . . . . 27

,Dec  . . . . . . . . . . . . . . gan. 1g . . . . . . . . . . . .  iljan  . . . . . . . . . . . . 

* ec . . . . . . . . . . . . . . an. . . . . . . . . . . . . ec . . . . . . . . . . . .

Dec 12 . . . . . . . . . . . . . . Jan. 6 . . . . . . . . . . . . 28 Jan . . . . . . . . . . . . 28

ec 13 . . . . . . . . . . . . . . Jan. 6 . . . . . . . . . . . . 27 Jan 9 . . . . . . . . . . . . 27

‘Dec 14 . . . . . . . . . . . . . . Jan. l1 . . . . . . . . . . . . 28 Jan . . . . . . . . . . . . 27

Dec 16 . . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . .. 26 Jan 12 . . . . . . . . . . .. 27

>Dec 17 . . . . . . . . . . . . .. Jan. 1O . . . . . . . . . . .. 15 Jan 17 . . . . . . . . . . .. 31

. ec 18 . . . . . . . . . . . . .. Jan. 16 . . . . . . . . . . .. 29 Jan 12 . . . . . . . . . . .. 25

{Dec 19 . . . . . . . . . . . . .. Jan. 13 . . . . . . . . . . .. 25 Jan 13 . . . . . . . . . . .. 25

93cc 2O . . . . . . . . . . . . . . Jan. 22 . . . . . . . . . . . . 33 Jan 19 . . . . . . . . . . . . 3O

r‘ ec 21 . . . . . . . . . . . . .. Jan. 13 . . . . . . . . . . .. 23 Jan 12 . . . . . . . . . . .. 22

j ec 22 . . . . . . . . . . . . .. Jan. 18 . . . . . . . . . . .. 27 Jan 19 . . . . . . . . . . .. 28

5 ec 23 . . . . . . . . . . . . . . Jan 21 . . . . . . . . . . . . 29 Jan 27 . . . . . . . . . . . . 35

tDec 24 . . . . . . . . . . . . . . Jan 19 . . . . . . . . . . . . 34 Jan 27 . . . . . . . . . . . . 34

Q ec 25 . . . . . . . . . . . . .. Jan 19 . . . . . . . . . . .. 32 Jan 19 . . . . . . . . . . .. 32

“Dec 26 . . . . . . . . . . . . . . Jan 11 . . . . . . . . . . . . 32 Jan 29 . . . . . . . . . . . . 32

iDec 27 . . . . . . . . . . . . . . Jan 21 . . . . . . . . . . . . 25 Jan 2O . . . . . . . . . . . . 24

fDec 3O . . . . . . . . . . . . . . Jan 19 . . . . . . . . . . . . 2O Jan. 2O . . . . . . . . . . . . 21
 1917

1133‘ 2 """"""""" ""123 §3":::::"::: 33 "lit 2%.::"::::"" g2
Qan 3 . . . . . . . . . . . . . . Jan 29 . . . . . . . . . . . . 26 Feb 5 . . . . . . . . . . . . 33

Jan 4 . . . . . . . . . . . . . . Feb 11 . . . . . . . . . . . . 38 Feb 7 . . . . . . . . . . . . 34

Jan b . . . . . . . . . . . . . . Feb 5 . . . . . . . . . . . . 3O Jan 28 . . . . . . . . . . . . 22

plan 7 . . . . . . . . . . . . . . Feb 3 . . . . . . . . . . . . 27 Feb 24 . . . . . . . . . . . . 48

flan 8 . . . . . . . . . . . . . . Feb 1O . . . . . . . . . . . . 29 Feb 19 . . . . . . . . . . . . 4O

’ an 9 . . . . . . . . . . . . . . Feb 18 . . . . . . . . . . . . 4O Feb 2O . . . . . . . . . . . . 42

iJan 1O . . . . . . . . . . . .‘. . Feb 16 . . . . . . . . . . . . 37 Feb 21 . . . . . . . . . . . . 42

Jan 11 . . . . . . . . . . . . . . Feb 17 . . . . . . . . . . . . 37 Feb 27 . . . . . . . . . . . . 37

Jan 12 . . . . . . . . . . . . . . Feb 9 . . . . . . . . . . . . 28 Feb 22 . . . . . . . . . . . . 41

Jan 13 . . . . . . . . . . . . . . Feb . . . . . . . . . . . . 23 Mar . . . . . . . . . . . . 5O

Jan l7 . . . . . . . . . . . . . . Feb 19 . . . . . . . . . . . . 33 Feb 22 . . . . . . . . . . . . 36

Jan 18 . . . . . . . . . . . . . . Feb 13 . . . . . . . . . . . . 26 Feb 27 . . . . . . . . . . . . 4O

Jan 19 . . . . . . . . . . . . . . Feb 21 . . . . . . . . . . . . 33 Feb 13 . . . . . . . . . . . . 25

Jan 2O . . . . . . . . . . . . . . Feb 22 . . . . . . . . . . . . 33 Feb 24 . . . . . . . . . . . . 35

Jan 21 . . . . . ., . . . . . . . Feb 16 . . . . . . . . . . . . 26 Feb 22 . . . . . . . . . . . . 33

Jan 23 . . . . . . . . . . . . . . Feb 22 . . . . . . . . . . . . 30 Feb 21 . . . . . . . . . . . . 29

Jan 25 . . . . . . . . . . . . . . Feb 14 . . . . . . . . . . . . 20 Feb 22 . . . . . . . . . . . . 28

Jan 26 . . . . . . . . . . . . . . Feb 21 . . . . . . . . . . . . 26 Feb 25 . . . . . . . . . . . . 3O

Jan 27 . . . . . . . . . . . . . . Feb 26 . . . . . . . . . . . . 3O Feb 24 . . . . . . . . . . . . 28

Jan 28 . . . . . . . . . . . . . . Feb 27 . . . . . . . . . . . . 3O Feb 26 . . . . . . . . . . . . 29

Jan 29 . . . . . . . . . . . . . . Feb 27 . . . . . . . . . . . . 29 Feb 26 . . . . . . . . . . . . 28

léan. 3O . . . . . . -. . . . . . . . Feb. 28 . . . . . . . . . . . . 29 Mar. 3 . . . . . . . . . . . . 31

 131L112 . . . . . . . . . . . . .. Feb. 28 . . . . . . . . . . .. 26 Feb. 26 . . . . . . . . . . .. 24
l.
E1
5

_ Temperature apparently is an important factor in the length of the
life period. When the temperature drops there is a corresponding in-
Qcrease in the length of the life period. The fatal lOW temperature has
Linot been determined.

Proportion of Sexes.

o Of the 2942 individuals which emerged in the laboratory from Jan-
.f11ary, 1916, to May, 1917, 1494, or slightly more than 50 per cent.,
‘were males, while 1448, a little less than 5O per cent, were females.
{Table 21 shows the proportion of sexes by months. It is interesting
Etc note that the numbers are very nearly equal throughout the entire
eperiod. There is a slight increase in females during the cold period
and males are more abundant during the warmer period. In the field
the proportion of sexes is likewise very nearly equal. Out of 243
Eweevils collected at various dates during the summer of 1916, 117, or

 

50 _ TEXAS AGRICULTURAL EXPERIMENT STATION.

about 48 per cent., were females; 126, slightly less than 52 per cent,
were males. The male is readily attracted to the female, and in the;
field the active female is usually attended by one and occasionally by’
several. Of the inactive weevils or those in places of hiding, approxi-f
mately an equal number of males and females Were collected. 5

Table 21.—-Proportion of Sexes. 

i

Number Mean Mean

Date Emerged Males Females Temp. Humidity f
1916
January . . . . . . . . . . . . . . . . . . . . . . . 77 36 41 56.9 78.9

February . . . . . . . . . . . . . . . . . . . . . . 34 14 20 55.0 66.7

March . . . . . . . . . . . . . . . . . . . . . . . . . 140 73 67 66.4 61.8

A ril . . . . . . . . . . . . . . . . . . . . . . . . .. 125 61 64 68.9 73.0

ay . . . . . . . . . . . . . . . . . . . . . . . . .. 350 190 160 79. 6 71.7

June . . . . . . . . . . . . . . . . . . . . . . . . .. 284 146 138 86. 0 71.0

J y . . . . . . . . . . . . . . . . . . . . . . . . .. 201 111 0 87.0 69.0

August . . . . . . . . . . . . . . . . . .  . . . . 194 98 96 86.0 68.5

September . . . . . . . . . . . . . . . . . . . . . 226 122 104 83. 5 63.0

October . . . . . . . . . . . . . . . . . . . . . . . . ' 209 105 104 73. 0 63. 5

November . . . . . . . . . . . . . . . . . . . . . 96 49 47 68. 5 69. 5

December . . . . . . . . . . . . . . . . . . . . . . 175 91 84 64. 6 64. 5
1917 . .
January . . . . . . . . . . . . . . . . . . . . . . . 87 35 52 60.3 70.9
February . . . . . . . . . . . . . . . . . . . . . . 194 93 101 62.0 58.7
March . . . . . . . . . . . . . . . . . . . . . . . . . 330 165 165 68. 7 63 .0
April . . . . . . . . . . . . . . . . . . . . . . . . . . 220 105 115 71.4 63.7
n:

Location of Food.

The adult Weevil has fully developed wings but cannot be considered
a strong flier. If disturbed it Will take to flight very readily, but the
distance of a continuous flight has rarely been observed to exceed 100
yards and is usually much shorter. By intermittent flights, the weevil
is able to cover considerable distance, and doubtless flight is an im-
portant means of dissemination in the field. The most isolated patches
of cowpeas are usually found to be infested with the insect. The
cowpeas grown on the experimental plats of the Division of Entomology
were infested during the summers of 1915, 1916, and 1917, notwith-
standing the fact that no other cowpeas were growing nearer than a
mile away. The infestation was particularly severe during the sum-
mer of 1916. Owing‘ to a lack of rain, the cowpeas in the immediate
vicinity were to a large extent a failure, and the weevils seemed there-
fore to concentrate on the cowpeas growing on the experimental plats;
these cowpeas had been irrigated and produced a normal growth. No
migration in pronounced numbers has been observed to take place, as
is often the case with other insects. If the food is depleted the num-
ber of weevils gradually‘ decreases, but as long as any cowpeas remain
in the field, a few isolated individuals can usually be found, and
weevils have been collected in patches after the peas have been har-
vested. In confinement the weevil is likewise very aggressive in its
search for food, peas left exposed in the laboratory were discovered
and attacked with an uncanny precision. Even a single isolated pea
in the most remote corner or nook if accessible to the weevil is attacked
and will soon have eggs adhering to it. ‘Mating; is conducive to a
more insistent search for food.

THE OowPEA “TEEVIL. - 51

Adaptive Capacity.

There is a very little flexibility in the habits of this insect to adapt
itself to a strange environment. This is particularly true with respect
"to its food plant. Changing the food from one variety of cowpea to
another did not apparently affect the weevil, but When a nearly
‘related food plant, such as certain varieties of beans, navy, and lima,
Were repeatedly tried, the Weevil could not complete its life cycle. In
all experiments egg deposition took place readily enough, as has been
elsewhere stated. The eggs hatched in a large percentage of cases, but
the larvae could not subsist in the substituted food, and all were dead
Within three days after hatching. In the field the cowpea Weevil has
not been collected consistently on any plant except cowpeas. When
the food is removed the weevils probably disseminate from that point

‘to other patches of cowpeas, instead of attacking other plants groxving

adjacent to infested patches. The weevil is restricted to the coWpea

as a food plant.

Copulatioiz.

Copulation is generally of short duration, rarely comprising more
than three or four minutes. In the laboratory on September 8, 1916,
ten pairs of weevils were timed While copulating. The average time
Was three minutes and twenty seconds. The male normally is ag-
gressive and insistent and continues to follow the female about very
closely. The attraction of the male to virgin females two or three
days old is much more pronounced than to the newly emerged indi-
viduals. When the female is in a receptive mood she remains very
quiet; usually is motionless and exhibits no excitement, while the male
appears to be very nervous. At the beginning of coitu the male strokes
the female with his antennae. Without exception the female makes
the initial attempt at release; the male appearing helpless to extricate
himself. The separation is accomplished by the female’s pushing against
the male with her hind legs, a few vigorous backward strokes usually
suificing. The male during this time remains perfectly quiet. Some-
times, however, several minutes are required before the separation is
completed. In the laboratory copulation took place freely in any.
temperature sufficient to maintain activity among‘ the weevils. The
total number of eopulations occurring during the life of a female varies
under different conditions.

As many as three often occur and have been observed at various
times in the life history studies on the insect. Intermating is a com-
mon occurrence. The female Will readily unite with any male, at a
propitious time even if she has already mated to another male. The
male is no more pronounced in his instinct for choosing a mate and
will unite with any female regardless of any previous mating with
other individuals.

The total number of females that a single male can fertilize has
been determined by laboratory experiments. The average of ten males
mated in each case to virgin females, resulted in eight females fertilized
in five days. Sometimes mating will take place after the male is no
longer capable of fertilizing the female. The average time that these
"males lived was seven days.

52 TEXAS AGRICULTURAL EXPERIMENT STATION.

Period Between Maturity and Copulation.

The period between maturity and copulation is very short. On
August 20, 1916, in the laboratory, Courtney noted a pair of weevils
in copulation one minute after they had emerged. This was doubtless

"an extreme case and does not occur frequently. During the warm

season when the activity of the weevils is at a maximum, the actual
time which elapses between maturity and copulation ranges from five
minutes, which was frequently observed in the laboratory throughout
the summer of 1916, to a maximum that is determined only by the
ability of the male to come into contact with the female. It might
be said that the insect is ready to mate and begin reproduction almost
immediately after maturity and emergence. The average time occur-
ring between maturity‘ and copulation was not definitely determined,
but it is safe to assume that it is not over 24 hours and probably less.
In Table 23 it will be noted that egg deposition took place invariably
on the day following mating, over the entire period. No eggs were
deposited by an unmated female.

Fertility.

One mating is sufiicient to fertilize the entire egg quota of the
female. If the male dies or is removed after copulation has taken
place, all the eggs deposited by the female are fertile and will hatch,
However, successive matings seem to stimulate the female to further
egg deposition. The per cent. of normally deposited eggs that were
unfertile or that did not hatch, over the entire period of the life history
notes, was very small, in fact, it could well be considered negligible.
Sometimes the egg is insecurely stuck to the pea and is brushed off,
or it may be stuck at only one side or on the end and lifted away from
the surface of the pea. These eggs were not observed to hatch. All
experiments conducted in the laboratory attempting to induce unmated
females to deposit eggs produced negative results.

Oviposition.

Oviposition is usually a short simple process. The female crawls
about the seed in search of a favorable place for egg deposition. When
the pea has been selected, the female explores the surface with her
antennae. She stops and remains quiet for a few moments. The tip
ofthe abdomen, which is protruded, is then bent well under the body
and rubbed on the surface and immediately a clear sticky fluid is
exuded; the egg follows shortly and is placed in the midst of this
material which soon hardens and attaches the egg firmly to the surface
of the pea. Sometimes the female turns about and examines the egg
with her antennae. The entire operation is often completed within
a minute. Sometimes after resting a few seconds, the female repeats
the operation; usually, however, three or four minutes, often a much
longer time elapses between deposition of eggs. When the supply of
seed is abundant one egg is usually placed on a pea, but very often two
or three, and occasionally more may be found on a single pea. When
the supply of seed is small, however, or the infestation of weevils great,

THE OowPEA WEEVIL. 53

very often a single seed containing twenty or thirty eggs may be found.
On October 19, 1916, a medium sized cowpea of the Chinese Red variety
was found in the field, with forty-founeggs adhering to it.

The minimum average mean temperature at which oviposition took
place was 33 degrees F. Only a few eggs were deposited in a tempera-
ture below 5O degrees. When the temperature drops below '70 degrees
there is, however, a noticeable decrease in oviposition. The optimum
temperature for oviposition ranges between 85 and 95 degrees F. Fe-
males will oviposit on any foreign objects if cowpeas are inaccessible.
Frequently the eggs adhered to the sides of the vials. Temperature
greatly influences the rate of oviposition and the total number of eggs
deposited. The average number of eggs produced per female for the
year 1916 was '73. The average mean temperature for the year was
72.9 degrees F. i

Age at Beginning of Oviposition.

The age at which the female begins ovipositing varies greatly with
the season. The relationship of temperature to the age at beginning
of oviposition is very pronounced. In Table 23 the daily egg produc-
tion with the maximum, minimum, and mean daily temperature and
humidity, is given. The longest period recorded, 1G days, occurred but
once. Female No. 371, mated on January 10, 1917, deposited her first
eggs on January 26, 1917. During this period the mean temperature
ranged from a maximum of 76 degrees to a minimum of 30 degrees F.,
with a daily mean average of 53 degrees F. A period of from 3 to 5
days occurred frequently during the winter months of December, Jan-
uary, and February of both 1916 and 1917. When the mean tempera-
ture was 65 degrees F. or above, oviposition invariably took place on
the same day that mating occurred. p

Throughout the summer months of 1916 frequent observations were
made in the laboratory, in which cases the female began oviposition‘ in
from 3 to 5 minutes after mating. On October 16, 1915, Courtney
noted an extreme case, a female depositing an egg in less than one
minute after mating. ‘The average period is much longer.

In a temperature of 70 degrees F. or above, the female will always
begin oviposition within a period of 24 hours if she has been mated with

an active male. When a female has been mated and does not have -

access to cowpeas the time until oviposition begins is much prolonged.
On September 12, 1916, fifteen females were placed in separate empty
vials and the average time until eggs were deposited on the sides of the
vials was slightly over three days. Showing that the female can con-
trol, within certain limits, the time at which oviposition begins.

Period 0f O/viposition.

The length of the period of oviposition, from October 1, 1915, to
February 1, 1917, is given in Table  The period ranges from a
minimum of 4 "days, which occurred frequently throughout the warm
months, to a maximum of 34 day's, which was noted on January 10,
1917’. This long period occurred but once in the entire stuiilies. The
daily mean temperature for this period ranged from 34 to 83 degrees

Q34 TEXAS idGRICULTURAL EXPERIMENT STATION.

~F'., with an average mean temperature of slightly less than 56 degrees F.
Eggs were deposited over a period of 28 days by three females during
December, 1916. In a warm temperature activity is much more pro-
nounced and the rate of oviposition is larger. When a female has laid
her entire quota of eggs she becomes sluggish and usually dies in a few
days. This greatly decreases the period for the warm months. In the
cold season when the mean temperature is 50 degrees F. or below,
activity is likely to cease altogether, and the weevils will seem dead
t0 all outward appearances. ‘With a rise in temperature, however, they
quickly resume a normal activity and egg laying continues. Within
certain limits the length of the period of oviposition varies in direct
proportion to the concurrent temperature.

Table 22.——Period of Oviposition.

_ ’ ' _ Temperature
First Egg Last Egg Period, - _
c Days Max. Min. Mean
1915
Oct 1 . . . . . . . . . . . . . Oct. . . . . . . . . . . . . 9 85 69 77.3

Oct 7 . . . . . . . . . . . . . Oct. 15 . . . . . . . . . . . . 9 86 7O 78. 6

Oct 7 . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 6 85 69 79.3

Oct 15.- . . . . . . . . . . . . Oct. 21 . . . . . . . . . . . . 7 85 70 78.3

Oct 15 . . . . . . . . . . . . . Oct. 19 . . . . . . . . . . . . 5 85 70 79.6

Oct 17 . . . . . . . . . . . . . Oct- 26 . . . . . . . . . . . . 10 85 68 75.5

Oct 18 . . . . . . . . . . . . . Oct. 23 . . . . . . . . . . . . 6 84 68 76.2

Oct 19 . . . . . . . . . . . . . Oct. 30 . . . . . . . . . . . . 12 83 68 74.4

Oct 20 . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 1 78 68 73.9

Oct 22 . . . . . . . . . . . . . Oct. 29 . . . . . . . . . . . . 78 68 73.6

Oct 24 . . . . . . . . . . . . . Nov. 2 . . . . . . . . . . . . 10 8O 69 74. 9

Oct 24 . . . . . . . . . . . . . Nov. 2 . . . . . . . . . . . . 10 80 69 74.9

Oct 25 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . . . 8 79 71 74.7

Oct 26 . . . . . . . . . . . . . Oct 31 . . . . . . . . . . . . 6 79 72 75. 0

Oct 27 . . . . . . . . . . . . . Oct 3O . . . . . . . . . . . . 4 79 72 75.3

Oct 28 . . . . . . . . . . . . . Nov 2 . . . . . . . . . . . . 6 80 72 76.3

Oct 29 . . . . . . . . . . . . . Nov 4 . . . . . . . . . . . . 7 81 66 75.5

Oct 30 . . . . . . . . . . . . . Nov 7 . . . . . . . . . . . . 9 81 66 75.4

Nov 1 . . . . . . . . . . . . .. Nov 8 . . . . . . . . . . .. 8 81 66 75.6

Nov 3 . . . . . . . . . . . . . Nov . . . . . . . . . . . . 7 82 66 75. 8

Nov 4 . . . . . . . . . . . .. Nov 11 . . . . . . . . . . . . 8 83 66 75.8

Nov 8 . . . . . . . . . . . . . Nov 11 . . . . . . . . . . . . 4 83 76 78.2

Nov 8 . . . . . . . . . . . . . Nov . . . . . . . . . . .. 1 8O 77 79. 5

Nov 10 . . . . . . . . . . . .. Nov 16 . . . . . . . . . . .. 7 83 57 68.8

Nov 10 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 12 86 57 72.0

Nov 11 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 11 86 57 71.5

Nov 12 . . . . . . . . . . . .. Nov 19 . . . . . . . . . . .. 8 84 57 70.3

Nov 13 . . . . . . . . . . . .. Nov 19 . . . . . . . . . . .. 7 84 57 70.8

Nov 14 . . . . . . . . . . . .. Nov 19 . . . . . . . . . . .. 6 87 57 71.1

Nov 15 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 7 86 57 73.0

Nov 16 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 6 86 58 74.2

Nov 17 . . . . . . . . . . . .. Nov. 21 . . . . . . . . . . .. 5 86 69 75.6

Nov 18 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 4 86 69 75.4

Nov 19 . . . . . . . . . . . .. rNov 24 . . . . . . . . . . .. 6 87 66 75.6

Nov 2O . . . . . . . . . . . .. Nov 26 . . . . . . . . . . .. 7 87 66 76.2

‘Nov 21 . . . . . . . . . . . .. Nov 26 . . . . . . . . . . .. 6 87 66 76.1

Nov 22 . . . . . . . . . . . .. Nov 28 . . . . . . . . . . .. 7 87 66 76.1

Nov 23 . . . . . . . . . . . . . Dec 1 . . . . . . . . . . . . 9 86 66 76.7

Nov 24 . . . . . . . . . . . .. Nov 30 . . . . . . . . . . .. 7 82 70 76.0

Nov 25 . . . . . . . . . . . . . Nov 3O . . . . . . . . . . . . 6 82 70 76.5 '

Nov 26 . . . . . . . . . . . . . Dec 2 . . . . . . . . . . . . 7 86 68 77.0

Nov 27 . . . . . . . . . . . . . Dec 2 . . . . . . . . . . . . 6 86 68 76.7

Nov 28 . . . . . . . . . . . . . Dec 6 . . . . . . . . . . . . 9 86 68 77.1

Nov 29 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 7 86 67 77.1

Nov 30 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 6 86 .67 77.5

Dec 1 . . . . . . . . . . . . . Dec 5 . . . . . . . . . . . . 5 86 68 77.8

Dec 2 . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 7 85 68 76.7

Dec 3 . . . . . . . . . . . . . Dec . . . . . . . . . . . . 7 85 68 75.7

Dec 4 . . . . . . . . . . . . . Dec 14 . . . . . . . . . . . . 11 85 43 67.7

Dec 5 . . . . . . . . . . . .. Dec 1O . . . . . . . . . . .. 6 85 43 75.0

Dec 6 . . . . . . . . . . . . . Dec 18 . . . . . . . . . . . . 11 83 39 74.6

Dec 7 . . . . . . . . . . . . . Dec 27 . . . . . . . . . . . . 21 83 35 56.5

Dec 8 . . . . . . . . . . . . . Dec 23 . . . . . . . . . . . . 16 83 35 56.8

Dec 9 . . . . . . . . . . . . . . Jan 8 . . . . . . . . . . . . 31 83 29 64.5

Dec 10 . . . . . . . . . . . . . Jan 11 . . . . . . . . . . . . 33 83 29 56.0

Dec 13 . . . . . . . . . . . . . Jan. 11 . . . . . . . . . . . . 3O 79 29 55. 5

THE COWPEA W EEVIL. 55
Table 22.—Period of Oviposition.—Continued.
Temperature
First Egg Last Egg Period, _
Days Max Min. Mean
1915
Dec. 14 . . . . . . . . . . .. Jan 9 . . . . . . . . . . .. 27 79 29 62.6

Dec 14 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 23 74 29 54.5

Dec 14 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 23 74 29 54.5

Dec 15 . . . . . . . . . . . .. Jan 9 . . . . . . . . . . .. 26 74 29 54.9

Dec 16 . . . . . . . . . . . .. Jan 5 . . . . . . . . . . .. 21 74 29 54.3

Dec 22 . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 21 79 29 56.3

Dec 23 . . . . . . . . . . . . . Jan . . . . . . . . . . . . 15 79 29 57. 0

Dec 21 . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 22 79 29 56.0

Dec 27 . . . . . . . . . . . . . Jan. 6 . . . . . . . . . . .. 11 79 29 58.5

Dec 27 . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . .. 16 79 29 58.1

Dec 28 . . . . . . . . . . . .. Jan. 5 . . . . . . . . . . .. 9 75 29 56.6

Dec 31 . . . . . . . . . . . .. Jan. 11 . . . . . . . . . . .. 12 79 30 62.3
1916
Jan. 1 . . . . . . . . . . . .. Jan 11 . . . . . . . . . . .. 11 79 45 62.7

Jan. 4 . . . . . . . . . . . .. Jan 12 . . . . . . . . . . .. 9 79 45 62.0

Jan. 12 . . . . . . . . . . . .. Jan 21 . . . . . . . . . . .. 1O 79 22 48.0

Jan. 2O . . . . . . . . . . . .. Jan 21 . . . . . . . . . . .. 2 71 38 59.0

Jan. 21 . . . . . . . . . . . .. Feb 20 . . . . . . . . . . .. 31 80 26 54.7

Jan. 26 . . . . . . . . . . . .. Feb 21 . . . . . . . . . . .. 27 8O 26 54.2

Jan. 26 . . . . . . . . . . . .. Jan. 26 . . . . . . . . . . .. 1 73 59 66.0

Feb. 11 . . . . . . . . . . . .. Feb. 24 . . . . . . . . . . .. 14 80 39 58.8

Feb. 17 . . . . . . . . . . . .. Mar. 8 . . . . . . . . . . .. 21 84 39 60.8

Mar. 7 . . . . . . . . . . . .. Mar 19 . . . . . . . . . . .. 13 86 39 66.0

Mar. 7 . . . . . . . . . . . .. Mar. 19 . . . . . . . . . . . . 13 86 39 66.0

Mar. 9 . . . . . . . . . . . .. Mar. 17 . . . . . . . . . . . . 9 86 44 64.1

Mar 10 . . . . . . . . . . . .. Mar. 21 . . . . . . . . . . .. 12 88 44 67.6

Mar. 10 . . . . . . . . . . . .. Mar. 19 . . . . . . . . . . . . 1O 86 44 66.0.

Mar 17 . . . . . . . . . . . . . Mar. 3O . . . . . . . . . . . . 14 89 45 69.3

Mar 20 . . . . . . . . . . . .. Mar. 31 . . . . . . . . . . . . 12 89 48 70.4

Mar 21 . . . . . . . . . . . . . Mar. 31 . . . . . . . . . . . . 11 89 48 70.1

Mar 23 . . . . . . . . . . . .. April 4 . . . . . . . . . . .. 13 86 48 67.5

Mar 24 . . . . . . . . . . . .. April 4 . . . . . . . . . . . . 12 86 48 67.1

Mar 29 . . . . . . . . . . . . . April 22 . . . . . . . . . . . . 25 87 4O 68.1

Mar 3O . . . . . . . . . . . . . April 12 . . . . . . . . . . . . 14 83 55 64.7

April 2 . . . . . . . . . . . . . pril 14 . . . . . . . . . . . . 13 83 4O 64.8 -

April 4 . . . . . . . . . . . . . April 16 . . . . . . . . . . . . 13 83 40 65. 7

April 7 . . . . . . . . . . . . . April 19 . . . . . . . . . . . . 13 87 4O 66. 6

April 8 . . . . . . . . . . . . . pril 1 . . . . . . . . . . . . 12 87 40 _ 67. 6

April 11 . . . . . . . . . . . . . April 20 . . . . . . . . . . . . 10 87 53 72. 3

April 12 . . . . . . . . . . . . . April 21 . . . . . . . . . . . . 10 87 56 72.8

April 13 . . . . . . . . . . . . . April 23 . . . . . . . . . . . . 11 87 56 72.9

April 14 . . . . . . . . . . . . . April 23 . . . . . . . . . . . . 10 87 56 72.6

April 15 . . . . . . . . . . . . . April 23 . . . . . . . . . . . . 9 87 - 56 72. 1

April 17 . . . . . . . . . . . . . pril 23 . . . . . . . . . . . . 7 87 58 73.4

April 18 . . . . . . . . . . . . . April 3O . . . . . . . . . . . . 13 87 52 71.9

April 19 . . . . . . . . . . . . . April 25 . . . . . . . . . . . . 7 87 58 74. 5

April 21 . . . . . . . . . . . . . April 30 . . . . . . . . . . . . 10 87 52 70.7

April 22 . . . . . . . . . . . . . May 4 . . . . . . . . . . . . 13 87 52 71.3

April 24 . . . . . . . . . . . . . May 3 . . . . . . . . . . . . 10 87 52 70.4

April 25 . . . . . . . . . . . . . May 4 . . . . . . . . . . . . 10 87 52 70.3

April 26 . . . . . . . . . . . . . May 6 . . . . . . . . . . . . 11 94 52 72.2

April 27 . . . . . . . . . . . . . May 7 . . . . . . . . . . . . 11 96 52 73.2

April 29 . . . . . . . . . . . . . May 6 . . . . . .~ . . . . . . 8 94 54 74.0

May 2 . . . . . . . . .. . May 8 . . . . . . . . . . .. 7 99 65 79.4

May 3 . . . . . . . . . . . .. May 8 . . . . . . . . . . .. 6 99 65 81.0

May 5 . . . . . . . . . . . .. May 5 . . . . . . . . . . .. 1 91 73 82.0

May 5 . . . . . . . . . . . .. May 13 . . . . . . . . . . .. 9 " 100 73 87.3

May 6 . . . . . . . . . . . .. May 13 . . . . . . . . . . .. 8 100 74 88.0

May 8 . . . . . . . . . . . .. May 14 . . . . . . . . . . .. 7 100 8O 89.0

May 9 . . . . . . . . . . . .. May 18 . . . . . . . . . . .. 10 100 70 86.1

May 1O . . . . . . . . . . . .. May 19 . . . . . . . . . . .. 10 98 70 84.4

May 12 . . . . . . . . . . . . .. May 22 . . . . . . . . . . .. 11 97 70 82.4

May 13 . . . . . . . . . . . .. ay 1 . . . . . . . . . . .. 9 97 70 82.1

May l5 . . . . . . . . . . . .. May 25 . . . . . . . . . . .. 11 97 70 81. 1

May 16 . . . . . . . . . . . .. May 16 . . . . . . . . . . .. 1 97 74 85.5

May 17 . . . . . . . . . . . . . May 25 . . . . . . . . . . .. 9 91 70 79.1

May 18 . . . . . . . . . . . . .. May 25 . . . . . . . . . . .. 8 91 70 79.0

May 19 . . . . . . . . . . . .. May 24 . . . . . . . . . . . . 6 91 7O 79. 1

May 20 . . . . . . . . . . . .. May 27 . . . . . . . . . . . . 8 91 71 80.6

May 22 . . . . . . . . . . . .. May 29 . . . . . . . . . . . . 8 87 71 80.5

May 23 . . . . . . . . . . . . . May 30 . . . . . . . . . . . . 8 89 71 80.8

May 24 . . . . . . . . . . . . . . May 29 . . . . . . . . . . . . 6 89 71 80.5

May 25 . . . . . . . . . . . . . May 30 . . . . . . . . . . . . 6 89 73 80.8

May 26 . . . . . . . . . . . . . une 2 . . . . . . . . . . . . 8 94 73 82.3

May 27 . . . . . . . . . . . . . June 2 . . . . . . . . . . . . 7 94 73 82.1

May 29 . . . . . . . . . . . .. June 5 . . . . . . . . . . . . 8 94 73 83.3 ‘

ay 30 . . . . . . . . . . . .. June 5 . . . . . . . . . . .. 7 94 74 83.8 _

May 31 . . . . . . . . . . . .. June 4 . . . . . . . . . . .. 5 94 77 ' 84.6

56 TEXAS AGRICULTURAL EXPERIMENT STATION.
Table 22.—Period of Oviposition.—Continued.
_ Temperature
Flrst Egg Last Egg Period,
Days Max Min. Mean
1916

June 1 . . . . . . . . . . . .. June 6.. 6 93 77 84.3

June 3 . . . . . . . . . . . .. June 8 . . . . . . . . . . .. 6 93 71 83.3

June 5 . . . . . . . . . . . .. une 12 . . . . . . . . . . .. 8 94 71 83.0

June 5 . . . . . . . . . . . .. June 11 . . . . . . . . . . .. 7 94 71 82.8

June 6 . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 8 94 71 82.8

June 7 . . . . . . . . . . . .. June 13 . . . . . . . . . . .. 7 94 71 82.3

June 8 . . . . . . . . . . . .. June 14 . . . . . . . . . . .. 7 90 71 82.4

June 9 . . . . . . . . . . . . . June 14 . . . . . . . . . . . . 6 90 72 83.5

June 1O . . . . . . . . . . . . . June 15 . . . . . . . . . . . . 6 9O 73 84.0

June 12 . . . . . . . . . . . .. June 17 . . . . . . . . . . .. 6 90 72 82.1

June 14 . . . . . . . . . . . .. June 19 . . . . . . . . . . .. 6 90 72 81.8

June 15 . . . . . . . . . . . .. June 21 . . . . . . . . . . .. 7 95 72 82.1

June 16 . . . . . . . . . . . .. June 20 . . . . . . . . . . .. 5 95 72 81.1

June 17 . . . . . . . . . . . .. June 23 . . . . . . . . . . . . 7 95 75 83.4

June 20 . . . . . . . . . . . . . June 25 . . . . . . . . . . . . 6 95 75 86.1

June 21 . . . . . . . . . . . . . June 25 . . . . . . . . . . . . 5 95 78 86.8

June 22 . . . . . . . . . . . . . June 28 . . . . . . . . . . . . 7 95 75 86.8 v

June 23 . . . . . . . . . . . . . June 29 . . . . . . . . . . . . 7 95 75 87.3

June 24 . . . . . . . . . . . . . June 29 . . . . . . . . . . . . 6 95 75 86.7

June 25 . . . . . . . . . . . .. June 25 . . . . . . . . . . .. 1 95 81 88.0

June 26 . . . . . . . . . . . . . July 2 . . . . . . . . . . . . 7 95 75 85.4

June 27 . . . . . . . . . . . .. July 2 . . . . . . . . . . .. 6 95 75 85.1 '

June 28 . . . . . . . . . . . .. July 5 . . . . . . . . . . .. 8 95 75 84.6

June 29 . . . . . . . . . . . .. July 5 . . . . . . . . . . .. 7 95 76 84.5

June 30 . . . . . . . . . . . .. July 5 . . . . . . . . . . .. 6 95 76 84.5

July 1 . . . . . . . . . . . .. July 5 . . . . . . . . . . .. 5 95 76 84.8

July 3 . . . . . . . . . . . .. July 9 . . . . . . . . . . .. 7 99 76 87.1

July 4 . . . . . . . . . . . .. July 8 . . . . . . . . . . .. 5 99 76 87.2

July 6‘ . . . . . . . . . . . .. July 11 . . . . . . . . . . .. 6 99 79 88.5

July 7 . . . . . . . . . . . .. July 12 . . . . . . . . . . .. 6 99 79 88.3

July 8 . . . . . . . . . . . . . .July 13 . . . . . . . . . . .. 6 99 79 87.8

July 10 . . . . . . . . . . . .. .July 16 . . . . . . . . . . .. 7 98 79 87.1

July 11 . . . . . . . . . . . .. July 15 . . . . . . . . . . .. 5 97 79 86.6

July 12 . . . . . . . . . . . .. July 15 . . . . . . . . . . .. 4 95 80 86.2

July 13 . . . . . . . . . . . .. July 17 . . . . . . . . . . .. 5 98 79 87.4

July 14 . . . . . . . . . . . .. July 21 . . . . . . . . . . .. 8 99 78 87.5

July 15 . . . . . . . . . . . .. July 19 . . . . . . . . . . .. 5 99 78 87.8

July 17 . . . . . . . . . . . .. July 22 . . . . . . . . . . .. 6 99 78 88.3

July 18 . . . . . . . . . . . .. July 23 . . . . . . . . . . .. 6 99 78 87.8

July 19 . . . . . . . . . . . .. July 24 . . . . . . . . . . .. 6 99 80 88.1

J uly 20 . . . . . . . . . . . . . July 24 . . . . . . . . . . . 5 99 80 88. 6

July 21 . . . . . . . . . . . .. July 24 . . . . . . . . . . .. 4 99 8O 88.6

July 22 . . . . . . . . . . . .. July 26 . . . . . . . . . . .. 5 99 80 88.2

July 24 . . . . . . . . . . . .. July 29 . . . . . . . . . . .. .6 99 80 87.6

July 25 . . . . . . . . . . . .. July 28 . . . . . . . . . . .. 4 98 80 87.0

July 26 . . . . . . . . . . . .. July 30 . . . . . . . . . . .. 5 97 80 86.0

July 27 . . . . . . . . . . . .. July 31 . . . . . . . . . . .. 5 97 78 86.0

July 28 . . . . . . . . . . . .. Aug. 3 . . . . . . . . . . .. 7 97 79 86.8

July 29 . . . . . . . . . . . .. Aug. 3 . . . . . . . . . . .. 6 97 79 86.9

July 31 . . . . . . . . . . . .. Aug. 5 . . . . . . . . . . . . 6 97 79 87.3

Aug. 1 . . . . . . . . . . . . . Aug. 7 . . . . . . . A. . . . 7 97 79 86.9

Aug. 3 . . . . . . . . . . . . . Aug. 9 . . . . . . . . . . . . 7 97 79 86.0

Aug. 4 . . . . . . . . . . . .. Aug 10 . . . . . . . . . . .. 7 96 78 85.3

Aug. -5 . . . . . . . . . . . . . Aug 10 . . . . . . . . . . . . 6 96 78 84.9

Aug. 7 . . . . . . . . . . . .. Aug 12 . . . . . . . . . . .. 6 95 78 85.3

Aug 9. . . . . . . . . . . . . Aug 12 . . . . . . . . . . .. 4 94 80 85.2

Aug 11 . . . . . . . . . . . . . Aug. 17 . . . . . . . . . . . . 7 96 75 87. 1

Aug 12 . . . . . . . . . . . . . Aug 16 . . . . . . . . . . . . 5 96 79 87. 1

Aug 12 . . . . . . . . . . . .. Aug 18 . . . . . . . . . . .. 7 96 75 86.2

Aug. 14 . . . . . . . . . . . . . Aug 23 . . . . . . . . . . . . 10 ‘ 100 75 87. 1

Aug. 15 . . . . . . . . . . . .. Aug 20 . . . . . \ . . . . . .. 6 95 75 85.8

Aug. 16 . . . . . . . . . . . .. Aug 22 . . . . . . . . . . .. 7 100 75 87.1

Aug. 17 . . . . . . . . . . . . . Aug. 23 . . . . . . . . . . . . 7 100 75 87.2

Aug. 18 . . . . . . . . . . . . . Aug. 24 . . . . . . . . . . . . 7 100 79 87.5

Aug. 19 . . . . . . . . . . . . . Aug. 24 . . . . . . . . . . . . 6 100 79 87.7

Aug. 21 . . . . . . . . . . . . . Aug. 26 . . . . . . . . . . . . 6 100_ 70 86.0

Aug. 22 . . . . . . . . . . . . . Aug. 27 . . . . . . . . . . . . 6 97 70 84.6

Aug. 23 . . . . . . . . . . . . . Aug. 29 . . . . . . . . . . . . 7 96 70 84.0

Aug. 24 . . . . . . . . . . . . . Aug. 27 . . . . . . . . . . . . 4 93 70 83.0

Aug. 25 . . . . . . . . . . . . . Sept. 2 . . . . . . . . . . . . 9 97 70 85.0

Aug. 26 . . . . . . . . . . . . . . Sept. 2 . . . . . . . . . . . . 8 97 70 85.3

Aug. 28 . . . . . . . . . . . . . Sept. 3 . . . . . . . . . . . . 7 97 77 87.5

Aug. 29 . . . . . . . . . . . . . Sept. 4 . . . . . . . . . . . . 7 97 77 86.8

Aug. 30 . . . . . . . . . . . . . Sept. 4 . . . . . . . . . . . . 6 97 77 87.0

Sept. 1 . . . . . . . . . . . .. Sept. 7 . . . . . . . . . . .. 7 97 79 88.0

Sept 2 . . . . . . . . . . . . . Sept. 8 . . . . . . . . . . . . 7 101 80 88.7

Sept 3 . . . . . . . . . . . . . Sept 7 . . . . . . . . . . . . 5 97 80 88.6

Sept 4 . . . . . . . . . . . .. Sept 12 . . . . . . . . . . .. 9 101 80 88.7

Sept 5 . . . . . . . . . . . . . Sept 11 . . . . . . . . . . .. 7 101 80 88.8

THE OOWPEA WEEVIL.

Table 22.—Period of Ovipositiom-Continued.‘

57

_ Temperature
Flrst Egg Last Egg Period, . _
Days Max Mm. Mean
1916
Sept. 6 . . . . . . . . . . . . . Sept. 11 . . . . . . . . . . . . . 6 101 80 89.0

Sept. 7 . . . . . . . . . . . . . Sept. 12 . . . . . . . . . . . . 6 101 80 88.8

Sept. 8 . . . . . . . . . . . . . Sept. 15 . . . . . . . . . . . . 8 101 73 87.3

Sept. 9 . . . . . . . . . . . . . Sept. 13 . . . . . . . . . . . . 5 99 79 88.4

Sept. 10 . . . . . . . . . . . . . Sept. 14 . . . . . . . . . . . . 5 97 78 87.6

Sept. 11 . . . . . . . . . . . . . . Sept. 21 . . . . . . . . . . . . 11 99 67 82. 8

Sept. 12 . . . . . . . . . . . .. Sept. 17 . . . . . . . . . . . . 6 97 7O 83.3

Sept. 13 . . . . . . . . . . . . . Sept. 20 . . . . . . . . . . . . 8 99 67 81.7

Sept. 14 . . . . . . . . . . . . . Sept. 20 . . . . . . . . . . . . 7 99 67 80.8

Sept. 15 . . . . . . . . . . . . . Sept. 23 . . . . . . . . . . . . 9 99 67 80.2

Sept. 16 . . . . . . . . . . . . . Sept. 21 . . . . . . . . . . . . 6 99 67 79.8

Sept. 17 . . . . . . . . . . . . . Sept. 22 . . . . . . . . . . . . 6 99 67 80. 1

Sept. 18 . . . . . . . . . . . . . Sept. 25 . . . . . . . . . . . . 8 99 67 80.8

Sept. 19 . . . . . . . . . . . . . Sept. 25 . . . . . . . . . . . . 7 91 68 80.5

Sept. 20 . . . . . . . . . . . . . Sept. 25 . . . . . . . . . . . . 6 91 69 81.0

Sept. 22 . . . . . . . . . . . . . Sept. 29 . . . . . . . . . . . . 8 105 60 81.2

Sept. 23 . . . . . . . . . . . . . Sept. 28 . . . . . . . . . . . . 6 105 70 82.8

Sept. 24 . . . . . . . . . . . . . Oct. 1 . . . . . . . . . . . . 8 105 57 77.8

Sept. 25 . . . . . . . . . . . . . Oct. 6 . . . . . . . . . . . . 12 105 57 77. 2

Sept. 26 . . . . . . . . . . . . . Oct. 4 . . . . . . . . . . . . 9 105 57 76.5

Sept. 27 . . . . . . . . . . . . . Oct. 3 . . . . . . . . . . . . 7 105 57 76.1

Sept 28 . . . . . . . . . . . . . Oct. 5 . . . . . . . . . . . . 8 95 57 74.8

Sept 29 . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 9 89 57 73.9

Sept 30 . . . . . . . . . . . . . Oct. 7 . . . . . . . . . . . . 8 89 57 74.5

Oct. 1 . . . . . . . . . . . . . Oct. 8 . . . . . . . . . . . . 8 90 59 75.8

Oct. 3 . . . . . . . . . . . . . Oct. 9 . . . . . . . . . . . . 7 91 66 78.5

Oct. 4 . . . . . . . . . . . . . Oct. 9 . . . . . . . . . . . . 6 91 66 78.7

Oct. 5 . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 8 94 66 78.7

Oct. 6 . . . . . . . . . . . . . Oct. 12 . . . . . . . . . . . . 7 94 68 78.9

Oct. 7 . . . . . . . . . . . . . Oct. 14 . . . . . . . . . . . . 8 94 68 79.7

Oct. 8 . . . . . . . . . . . . . Oct. 13 . . . . . . . . . . . . 6 94 68 80.0

Oct. 9 . . . . . . . . . . . . . Oct. 15 . . . . . . . . . . . . 7 94 l 68 80.0

Oct. 10 . . . . . . . . . . . . . Oct. 19 . . . . . . . . . . . . 10 94 60 76.4

Oct. ll . . . . . . . . . . . . . Oct. 18 . . . . . . . . . . . . c8 90 61 76.8

Oct. 12 . . . . . . . . . . . . . Oct. 18 . . . . . . . . . . . . 7 90 61 76.6

Oct. 13 . . . . . . . . . . . . . Oct. 22 . . . . . . . . . . . . 10 9O 41 71.3

Oct. 14 . . . . . . . . . . . .. Oct. 22 . . . . . . . . . . .. 9 90 41 70.1

Oct. 15 . . . . . . . . . . . . . Oct. 26 . . . . . . . . . . . . 12 95 41 69.9

Oct. 16 . . . . . . . . . . . .. Oct. 30 . . . . . . . . . . .. 15 95 41 70.3

Oct. 17 . . . . . . . . . . . . . Oct. 30 . . . . . . . . . . . . 14 95 41 69.9

Oct. 18 . . . . . . . . . . . .. Oct. 3O . . . . . . . . . . .. 13 95 41 70.2

Oct. 19 . . . . . . . . . . . . . Oct. 31 . . . . . . . . . . . . 13 95 41 70.7

Oct. 20 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . .. 13 95 41 71.5

Oct. 21 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . . . 12 95 41 72.3

Oct. 22 . . . . . . . . . . . .. Oct. 31 . . . . . . . . . . .. 10 95 52 73.1

Oct. 23 . . . . . . . . . . . . . Nov. 2 . . . . . . . . . . . . 11 95 53 73. 5

Oct. 24 . . . . . . . . . . . . . Nov. 1 . . . . . . . . . . . . 9 95 53 74.8

Oct. 25 . . . . . . . . . . . . . Nov. 5 . . . . . . . . . . . . 12 92 53 74.8

Oct. 26 . . . . . . . . . . . . . Nov. 9 . . . . . . . . . . . . 15 92 53 74.8

Oct. 27 . . . . . . . . . . . . . Nov. 5 . . . . . . . . . . . . 10 92 53 75.3

Oct. 28 . . . . . . . . . . . . . Nov. 4 . . . . . . . . . . . . 8 90 56 75.2 .

Oct. 29 . . . . . . . . . . . . . Nov. 5 . . . . . . . . . . . . 8 90 60 76.3

Oct 30 . . . . . . . . . . . . . Nov. 7 . . . . . . . . . . . . 9 90 60 76.4

Oct 31 . . . . . . . . . . . . . Nov. 10 . . . . . . . . . . . . 11 89 60 74.6

Nov 1 . . . . . . . . . . . . . Nov. 9 . . . . . . . . . . . . 9 89 58 75. 7

Nov 2 . . . . . . . . . . . .. Nov. l0 . . . . . . . . . . .. 9 89 51 74.5

Nov 3 . . . . . . . . . . . .. Nov. l1 . . . . . . . . . . .. 9 87 51 74.0

Nov 4 . . . . . . . . . . . .. Nov. 11 . . . . . . . . . . .. 8 87 51 74.0

Nov 5 . . . . . . . . . . . .. Nov. 19 . . . . . . . . . . .. 15 89 33 67.0

Nov 6 . . . . . . . . . . . . . Nov. 23 . . . . . . . . . . . . 18 94 33 66.6

Nov 7 . . . . . . . . . . . .. Nov 21 . . . . . . . . . . .. 15 94 33 66.6

Nov 8 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 21 98 33 65.2

Nov 9 . . . . . . . . . . . . . Nov. 30 . . . . . . . . . . . . 22 98 33 65.8

Nov 10 . . . . . . . . . . . .. Nov. 28 . . . . . . . . . . . . 19 94 33 63.6

Nov 12 . . . . . . . . . . . . . Dec l . . . . . . . . . . . . 20 98 33 65.8

Nov 15 . . . . . . . . . . . . . Nov. 28 . . . . . . . . . . . . 14 94 33 64.1

Nov 15 . . . . . . . . . . . . . Nov 28 . . . . . . . . . . .. 14 94 33 64. 1

Nov. 19 . . . . . . . . . . . . . Dec 4 . . . . . . . . . . . . 16 98 44 70. 5

Nov. 20 . . . . . . . . . . . . . Dec 4 . . . . . . . . . . . . 15 98 44 70.6

Nov 21 . . . . . . . . . . . . . Dec 3 . . . . . . . . . . .. 13 98 44 69.2

Nov 23 . . . . . . . . . . . . . Dec 7 . . . . . . . . . . . . 15 101 44 72.8

Nov. 24 . . . . . . . . . . . . . Dec 6 . . . . . . . . . . . . 13 101 44 74.0

Nov 26 . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 13 101 44 75.3

Nov 28 . . . . . . . . . . . . . Dec 10 . . . . . . . . . . . . 13 101 38 75.0

gov 3O . . . . . . . . . . . . . Dec 8 . . . . . . . . . . . . 9 101 48 78.4

ec. 1 . . . . . . . . . . . . . Dec 14 . . . . . . . . . . . . 14 101 32 70.1

Dec 2 . . . . . . . . . . . .. Dec 12 . . . . . . . . . . . . 11 101 34 71.7

Dec 3 . . . . . . . . . . . . . Dec 16 . . . . . . . . . . . . 14 101 32 67.7

Dec. 4 . . . . . . . . . . . . . Dec 17 . . . . . . . . . . . . 14 101 32 67.0

58 TEXAS AGRICULTURAL EXPERIMENT STATION.

Table 22.—Period of Oviposition.—Continued.

_ Temperature

Period, _

Days Max. Min. Mean
Dec. 29 101 28 62. 5
Dec. 24 99 28 61.6
Dec. 28 92 28 60. 9
Dec. 28 9O 28 60. 8
Dec. 24 92 28 60.0
Dec. 24 92 ' 28 60.0
Dec. 25 92 28 60.8
Dec. 15 89 28 58.9
Dec. 22 92 28 60. 9
Dec. 21 92 28 61.0
Dec. 21 92 28 61.3
Dec. 23 93 28 63.0
Dec. 20 94 46 66.4
Dec. 17 93 46 66. 4
Dec. 17 93 46 66.4
Dec. 17 94 46 67.3
Dec. 15 92 46 66. 1
Dec. 15 93 46 67. 1
Dec. 18 94 44 67.0
Dec. 18 94 44 67.0
Dec. 15 94 46 67.2
Jan. 11 94 44 69. 6
Jan. 11 94 44 69.6
Jan. 10 95 44 68. 8
Jan. 24 » 94 30- 56. O
Jan. 24 94 30 55. 7
Jan. 22 94 3O 55.0
Jan. 22 100 3O 55.5
Jan. 34 100 25 56. 5
Jan. 24 100 25 57. 5
Jan. 26 100 25 57.4
Jan. 82 40 56.3
Jan. 20 100 25 58. 1
Jan. 24 100 25 57.4
Jan. 19 100 25 57.7
Jan. 27 103 25 61.2
Jan. 20 100 25 57. 1
Jan. 23 100 25 58.6
Jan. 25 103 25 61.0
Jan. 24 103 25 60. 1

Rate 0f Oviposition.

The rate of oviposition is shown in Table. 23. The maximum num-
ber of eggs produced in 24 hours was 58, by female N0. 251, on Sep-
tember 12, 1916. This maximum occurred but a single time during
the entire studies. From 50 to 55 eggs for a 24-hour period occurred
frequently during the warm months. Generally the maximum number
of eggs for a. 24-hour period is deposited immediately after mating. In
a few instances thelfemalc deposited her entire egg quota during the
first day after mating, and during the summer, it frequently happened
that she deposited all her eggs in the first two or three days. During
the second 24-hour period the number is reduced by about one-third.
In the succeeding periods there is a considerable fluctuation in the
number of eggs deposited. In a few instances, usually during the cold
periods, more eggs Were deposited on the fourth and fifth day than on
the preceding; days. During the warm season, however, the decline in
rate of oviposition after three days is very abrupt. Temperature has a
very important influence as will be seen from Table 23. In cold
weather the period of oviposition  greatly increased, while the rate of
oviposition suffers a corresponding decrease. No regularity appears in
the number of eggs deposited for any given period. In fact, the num-

THE CowPEA ll/VEEVIL. 59

ber of eggs deposited depends directly upon the prevailing temperature
for the period. The female may begin oviposition "with a single egg
and gradually 0r suddenly increase this t0 many times the number.
Sometimes two weeks or more may pass after mating before a single
egg is deposited, and occasionally it happens that the female will not
deposit any eggs during the period of her life. Records on the rate of
oviposition are given in detail in Table 23.

6C 'l‘ExAs AGRICULTURAL EXPERIMENT STATION.

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'74 “TEXAS AGRICULTURAL EXPERIMENT STATION.

 

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Table 23- Bate of Uviposition—-Continued.

THE COWPEA W EEVIL.

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'76

vip osition—C ontinued.

Table 23.—Rate of O

TEXAS AGRICULTURAL EXPERIMENT STATION.

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77

THE CQWPEA WEEVIL.

 

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78 Texas AGRICULTURAL EXPERIMENT STATION.

Generation Series.

In March, 1916, notes were begun on the number of generations that
are produced in a year under natural conditions. These notes were
made vsdthout interruption until March, 1917, and appear in detail in
Fig. 3. Two pairs of weevils, Nos. 1 and 2, were mated March 14,
1916, and the first weevils of the first eggs and the last weevils of the
last eggs are represented by the A and B series, respectively. A1 and
B1 indicate origin from the pair No. 1; F1, F2, F3, etc., represent the
filial generation. The last number to the right indicates the collection

of eggs from which the next generation was produced. This number, ~

in case of the first we-evils of the first eggs, would of course always be
one as will be seen in the A series in Fig. 3. In the last weevils of the
last eggs produced, however, the number varies from 3 to 11 because
all the pairs do not produce the same number of collections of eggs
even under the same conditions. Two pairs of weevils were used for
two reasons: to insure completion of notes for an entire year, and to
check the results. The above explanation applies to pair No. 2 also.

It will be seen in the chart that under the best conditions, by mating
the first female of each generation, nearly ten generations became pos-
sible in a year; and under the most adverse conditions, by mating the
last female of each generation, eight generations might be produced.
According to the average, it is safe to assume that normally nine gen-
erations are produced in a year in this locality.

Protection.

While the egg adheres to the external surface it is nevertheless pro-
tected to some degree by its semi-translucent color, which is not readily
observed on any of the light colored or mottled varieties of cowpeas.
The eggs are often placed in a depression or among other irregularities
on the surface of the peas. As has been stated, when the egg is de-
posited it is covered by a sticky fluid secreted by the female, which
hardens on exposure, forming a hard shell coating for the egg. Doubt-
less this affords much protection from crushing as the peas are Ihoved
about.

The entire under surface of the egg is glued securely to the pea,
and the larva’s access to the food supply is thus insured. The larva
enters the pea from the under side of the egg, and matures wholly
within the pea, which affords an excellent protection against parasites.
climatic conditions, or similar influences.

Adults protect themselves in several ways~—feigning death being the
most common. Upon the slightest disturbance, they immediately drop
and remain motionless, sometimes feigning death. for three or four
minutes. The weevils can run rapidlyr, and in nature it is difficult to
follow an individual which has been disturbed. They seek shelter quickly
and are greatly aided in this respect by their inconspicuous brownish-
black markings. Flight is another important protection. The weevil
will take to the wing very quickly if disturbed, and while it cannot be
classed as a strong flier, it is able to fly rapidly for short distances.
This without doubt enables it to elude many of its enemies.

79'

THE COWPEA XVEEVIL.

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- 80 TEXAS AGRICULTURAL EXPERIMENT STATION.

 

Mortality.

The rate of mortality resulting from adverse climatic conditions, is
very low. While the fatal low temperature has not been determined,
the adult weevils exposed to freezing temperatures revived apparently
unaffected. Peas containing eggs, developing larvae in all stages and
pupaewere likewise exposed to the lowest temperatures d.uring the win-
ters of 1916 and 1917. No appreciable increase in the rate of mortality
resulted; in fact, it was no greater than normally occurred, as shown
in the life history notes taken over the entire period.

At no time during the warm season does the heat become sufficiently
intense to destroy the developing weevils within the peas. Many in-
fested peas containing larvae and pupae that had been exposed to the
direct rays of the sun and the hottest weather occurring during the
summer. of 1916 and 1917, were taken into the laboratory, and the
adult weevils rarely failed to emerge.

Both adult weevils and developing larvae and pupae appear to be
very little aifected by a high or low humidity produced by artificial
means. Excessive rainfall probably destroys a number of the adults,
but_ there is no increase in mortality of the immature forms unless the
peas are submerged for a long time.

NATURAL CONTROL.
Parasites.

The larva of Britclzus quacZr-irnz/aculzztits is attacked by a parasite,
Bruchobius laticeps Ashmead.*- This species was described in Proc.
Nat. Mus, Vol. ~15, p. 7250, and. the original description is given below:

Female.——Type, length about 2.5 mm. Green, with brassy tinges;
head wider than thorax, head and thorax, including pleurae and pro-
podeum, with coarse thimble-like punctures, those on the mesonotum
so coarse as to somewhat resemble irregular reticulations; antennae
13-jointed, honey color, with three ring joints, the third subquadrate;
first joint of funicle almost twice as long as pedicel, the following joints
almost subequal in length, the second joint of funicle about two—thirds
as long as first; pronotum sharply truncate anteriorly; propodeum com-
pletely covered with thimble-like punctures, with lateral folds, the
spiracles large, elongate-ovate, situated basad; marginal vein short,
about one-third as long as submarginal; postmarginal slightly longer
than marginal; stigmal and marginal subequal in length; femora and
bases of tibiae reddish-honey color; rest of tibiae and tarsi whitish;
abdomen about as long as head and thorax combined.

Male. iLength about 1.75 mm. Similar to the female; antennae
with two ring joints, the third being elongated into a joint of the
tunicle, being as long as the pedicel, but not as long as the following
joint of the funicle; abdomen with a large basal white spot.

The type material consists of four females and four males and is
labeled “Washington, D. C, Nov. 12, 1896”; bred from Bruchus quadri-
maculatus. (F. C‘. Pratt, collector.)

*Detern1ined through the kindness of Dr. L. O. Howard.

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This parasite was first observed in the laboratory in August, 1916,
in some cowpeas heavily infested with the weevil, and collected during
July in the field at College Station, Texas. This parasite is shown in
Plate V (a) ; the males are on the right and the females 0n the left of
the photograph. The parasites were numerous and examination at that
time showed at least 1O per cent. of the weevil larvae parasitized.
Efforts to collect adult parasites in the field, however, resulted in the

' taking of only a few specimens. This parasite was also observed in
infested cowpeas collected at Lubbock, Texas. During the summer of
1917 no parasites were found at College Station, Texas. although care-

_ful search was made for them. As efforts to induce oviposition by
adult parasites proved unsuccessful, complete life history notes were not
made. The eggs are doubtless placed on the weevil larva or in the
larval burrow by means of a strong ovipositor with which the female
is equipped. The egg stage was not observed.

After hatching, the tiny parasite larva attaches itself to the weevil
larva and feeds externally. This is shown in Plate V (b) at the left
side 0f the photograph. The parasite increases in size very rapidly and
the host is usually not killed until it is nearly developed. By the time
it is fully matured and ready for pupation the entire body of the host,
except the head, has usually been consumed. Pupation takes place
within the larval burrow of the weevil. The adult parasite emerges
through a round hole similar to the weevil’s exit, except it is much
smaller. One parasite larva was observed to pupate September 23,
1916, and emerged as an adult October 1, 1916. The importance of
Bruchobius Zaticeps Ashmead, as a natural control, is questionable.
Though it undoubtedly destroys many weevil larvae, it does not appear
to be abundant enough to produce an appreciable reduction in the
number of weevils in this locality.‘

“THE OowPEA WEEVIL. l A 81

Egg Parasite.

The most important natural enemy of Bruchus quadrimaculatus is
Uscana scmi_fzam4lpenn,1's Girault,* a minute egg parasite which destroys
the weevil eggs in great numbers. The adult parasite is shown enlarged
in Plate V (c). The description of this species is given as it originally
appeared in Trans. Amer. Ent. Soc., Vol. 37, pp. 23-24.

Uscana, semifumipenazis Girault.

Female.—Length, 0.80 mm. Moderately small, visible easily to the
naked eye, but not casually even to the trained eye. General color
tawny yellow, the abdomen usually deep black, in some specimens vary-
ing to dusky yellowish, the legs dusky excepting the pallid yellow knees,
the tarsi (excepting the very slightly dusky terminal joint) and the
cephalic and intermediate tibiae; antennae dusky to pallid yellow; eyes
bright pinkish red; wings hyaline excepting the" proximal halves of the
fore wings, that portion proximad of the discal end of the venation,
which is distinctly though not pronouncedly, fumated; the fumated
area. extends to a point opposite the end of the stigmal knob and its

*Determined through the kindness of Dr. L. O. Howard.

82 TEXAS AGRICULTURAL EXPERIMENT STATION.

distal bounding line is nearly straight. Venation dusky. Body sculp-
ture inconspicuous. Colors of legs somewhat variable. Tegulae dusky
yellowish. l

Fore Wings with short marginal fringes along the cephalic margin,
which gradually slightly lengthen along the apex, becoming twice longer
at the disto-caudal apex of the wing, then gradually shortening again
caudad and proximad ; the longest cilia are not more than an eighth of
the greatest Wing width, which is near to, but not at the apex. The
discal ciliation is short and moderately close, arranged in about from
16 to 20 lines across the Widest portion of the wing. Marginal vein

broad, straight, twice the length of the stigmal and nearly a half shorter .

than the submarginal vein, truncate distad; submarginal vein narrow,
straight, but distad Where it curves cephalo-distad to join the marginal,
abruptly broader but not quite so broad as the latter. Oaudal wings
normal, the blade moderate in Width, acuminate, the marginal cilia
normal, those of the caudal margin as usual much longer, here grad-
ually lengthening distad where they are distinctly longer than the
greatest wing width, those of the cephalic margin usual, short; discal
ciliation of the caudal Wings consisting of three longitudinal lines of
cilia, the cephalic two paired, slightly converging distad, originating at
the apex of the marginal vein or nearly, the caudal line slightly fainter,
originating farther proximad, gradually converging on the others to-
ward the apex, nearer to, but not on, the caudal wing margin.

Antennae short and moderately stout, the club forming half of their
length, the scape short, not as long as the club, cylindrical, curved, the
pedicel shorter than the scape, not much longer than wide, conic to
subquadrate, subequal in length to the proximal club joint; ring joint
minute, flat, abruptly narrower than the pedicel or club; the three club
joints distinct, the intermediate joint l.ongest and widest (base), the
apical joint small, conic, acute; the club itself pointed conic-ovate in
shape. Pubescence of the antennae sparse, consisting of scattered long
hairs, mostly on the club. ,

From 30 specimens, g inch objective, 1 inch optic, Bausch and Lomb.

M aZe.~—-The same; the antennal club shorter, not as pointed.

From 13 specimens, §- inch objective, 1 inch optic, Bausch and Lomb.

Described from 13 males and 30 females mounted in balsam and
forming ‘a series of slides in the collections of the Bureau of Entomology,
U. S. Department of Agriculture, kindly loaned for study by Dr. L. O.
Howard and labelled as follows: ‘A‘Bred from Bean-weevil parasite
material from Beeville, Texas.—Honolulu, Haxvaii, October 30, 1909,
D. T. Fullowayn” Habitat.—-United States: Beeville, Texas.

This tiny insect, which is scarcely visible to the unaided eye, deposits
its egg inside the weevil egg. The parasite larva feeds upon the con-
tents of the weevil egg, which furnishes a sufficient food supply to reach
maturity. The adult parasite emerges from the host egg through a
minute round aperture, usually at the broad end of the egg.

The parasitized weevil egg first appears reddish yellow and grad-
ually turning darker as the‘ parasitedevelops, finally takes on a shiny
black color. The eggs on both the pods and seed are attacked, and
where they are grouped together it is unusual to find normal eggs on
the same seed with those that have been parasitized. One seed with

THE OowPEA WEEVIL. 83

twelve and another with eight parasitized eggs Were collected, the num-
bers ranging from three to five were much more common.

This parasite was first observed in the field in October, 1916, and at
that time appeared to be very abundant. Out of a total of 1621 Weevil
eggs examined during October, 1916, 1098, or over 67 per cent., were
parasitized, and 554. were normal.

Without question, this species, the importance of which is indicated
by the above figures, is the most effective factor in reducing the natural
increase of the pea Weevil in this locality.

REMEDIAL MEASURES.
Harvesting.

Proper harvesting of the cowpea crop will result in a reduction of
from 50 to 90 per cent. of the infestation of weevils. Where the crop
is permitted to remain in the field after it is fully matured, the tips of
the dry pods usually part sufficiently to expose the first two or three
seeds to weevil attack. Examination of a field of cowpeas in this con-
dition in October, 1916, showed that over 90 per cent. of the peas thus
exposed were infested by the weevil. The adult prefers to confine its
attack to the exposed seeil; obviously, if the crop is harvested at the
proper time, that is, before the pods open and the seeds are exposed,
the infestation can be materially checked. This may necessitate sev-
eral pickings and thus increase the cost of harvesting, but the reduction
in injury to the crop will more than justify the additional expenditure
of time and. labor.

Experiments conducted with the proper harvesting of cowpeas in

‘accordance with the recommendations given above, showed that 100 per

cent. weevil free seed could be obtained. Where the operations are
carried on in a commercial way, however, an infestation of from 2 to 5
per cent. may result from eggs that are deposited on the pods. This
cannot be eliminated because this insect cannot be combated by any
direct control measures in the field. It is therefore important to re-
member that proper harvesting is not recommended as a complete control
measure for the weevil. ln this connection, the crop should be treated
with either carbon bisulphide or heat as soon as possible after it is har-
vested in order to destroy any weevils not eliminated by precautions
taken in harvesting the crop.

Sltorage.

No matter how efiiciently the preventive measures have been carried
out, complete success depends upon the proper storage, since cowpeas
are always subject to reinfestation with the weevil. The popular belief
that “processed” (heated or furnigated) cowpeas will not become re-
infested, is erroneous. The cowpea weevil has been repeate-dlyr bred. in
hard,- dry, processed cowpeas, and apparently experienced no (lifficulty,
except that the period of development was greatly prolonged. R-egard-
less of the method employed in destroying the weevils in infested seed,
it should always be stored in a weevil-proof bin or other containers.
Seed in sacks is subject to infestation and should never be kept in
this condition exposed to the weevil. This was determined in an ex-

8a TEXAS AGRICULTURAL EXPERIMENT STATION.

perimental Way by exposing uninfested peas in a canvas sack to weevils.
Oviposition took place readily on the outside of the sack, and the
larvae succeeded in working through and infesting the seed within.
Weevil-proof bins constructed of tightly-fitted matched lumber, or tight-

ffitted metal containers have proved to be the most satisfactory method

of storing seed. The cost of such equipment varies with the size and
quality. The prevention of weevil injury makes it an economical
investment.

Fumigation With- Carbon Bisulphide.

Carbon bisulphide, which has been extensively used against insects
which infest stored seed, is, when properly used, one of the cheapest
and most effective methods of controlling the cowpea weevil. Chem-
ically pure liquid carbon bisulphide is colorless and completely volatile,
though the usual commercial product is yellowish in color because of
the presence of excess sulphur. It has a strong disagreeable odor and
evaporates rapidly on being exposed. The fumes of carbon bisulphide
are over twice as heavy as air and therefore will diffuse rapidly down-
ward. This is an important point to remember in the application of
this material. It should always be exposed above the seed to be treated.
The rapidity of irolatilization depends upon the surface of liquid exposed
to the air. Since rapid evaporation is desirable because the material
is an effective insecticide only in the gas form, the liquid should always
be exposed in large shallow containers to expedite evaporation. The
fumes have such penetrative power that it is possible to use this material
for treating seed in large quantities. Since it is confined space and
not the contents that determines the dosage, the seed to be treated
should be placed in as small a space as possible.

Tempe-rature has an important influence upon the effectiveness of
carbon bisulphide fumes, and unless the fumigation is conducted under
favorable conditions with respect to this factor, the results obtained
will not be satisfactory. The effectiveness of the fumes is materially
reduced at temperatures below 6O degrees F. Temperature governs the
amount of carbon bisulphide gas that is necessary to saturate the air.
The higher the temperature, the more carbon bisulphide is necessary
to saturate it, within certain limits. Evaporation of the liquid takes
place more slowly in lower temperatures, and more time will therefore
be required for the total dosage to become effective. It has been found
that active insects are more susceptible than inactive ones to the effects
of the gas, and insect activity varies directly with the increase of
temperature within certain limits.

Though the fumes from carbon bisulphide are highly inflammable,
and under certain conditions explosive, there is practically no danger
involved, if the proper precautions are taken. There must be no fire
or. source of fire near, while the fumigation is being done. If the

' va or is sufficiently dense, an ex losion mi ht result from even a small
P . P g

source of fire like a lighted cigar, or a spark from an electric light or
fan. In a temperature above 297 degrees F, the fumes may ignite
without the presence of flame. The extensive discussion of the danger
of the use of carbon bisulphide as a fumigant has resulted in a popular

opinion that many accidents occur “bygitsuse. jyhenjhevpfdargigziil-k

 .

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THE OowrEA WEEviL. 85
volved is understood, however, and the proper precautions in its use
are observed, the likelihood of any accident is removed.

The experiments giving the best results were conducted in a mean
average temperature ranging from 75 to 81 degrees F. This work
was done in the fumigation house shown in Plate V1’. The inside
measurements of this building are 8 feet by 8 feet by 8 feet, giving it a
contents of 512i cubic feet. It is tightly constructed throughout with
matched lumber. The sides and ceiling within are lined with beaver
board. The floor is constructed with a double layer of matched lumber,

and covered with a heavy coat of paint to make it impervious. The
total cost of

material and construction was $70.00.

Table 24.—Fumigation with Carbon Bisulphide.

E Temperature Humidity .,_.,
q; d.)
Charge Exposure '9 wt ‘O
1,000 Cu.Ft. § E _ _ g g
5 Z Max. Min. Mean Max. Min. Mean m x

9 pounds, . . . . 24 hours. . . . . E 43 88 63 75.5 58 44 51.0 0 100
9 pounds. . . . . 24 hours . . . . . . L 474 88 63 75.5 58 44 51.0 0 100
9 ounds. . . .. 24 hours. . .. . . P 134 88 63 75.5 58 44 51.0 0 100
C ec . . . . . . .. Untreated.... E 28 88 63 75.5 58 44 51.0 92.5
Check . . . . . . . . Untreated. . . . L 130 88 63 75.5 58 44 51.0 100.0 .

Check . . . . . . . . Untreated. . . . P 60 88 63 75. 5 58 44 51.0 100.0 . .. . .
6 pounds. . . .. 24 hours. . . . . E 133 94 63 78.5 54 13 33.5 0 100
6 pounds. . . . . 24 hours... . . . L 246 94 63 78.5 54 13 33.5 0 100
6 pounds. . . .. 24 hours. . . . . P 67 94 63 78.5 54 13 33.5 0 100
Check . . . . . . . . Untreated. . . . E 38 94 63 78. 5 54 13 33.5 92.1 . . . . .
Check . . . . . . . . Untreated. . . . - L 116 94 63 78.5 54 13 33. 5 100 . . . . .
Check . . . . . . . . Untreated. . . . P 106 94 63 78. 5 54 13 33.5 100 . . . . .
4 pounds. . . . . 24 hours. . . . . E 44 99 63 81 58 36 47 0 100
4 pounds. . . . . 24 hours. . .. . . L 470 99 63 81 58 36 47 0 100
4 pounds. . . . . 24 hours... . . . P 267 99 63 81 58 ‘ 36 47 O 100
Check . . . . . . . . Untreated. . . . E 48 99 63 81 58 36 47 89.8 . . . . .
Check . . . . . . . . Untreated. . . . L 50 99 63 81 58 .36 47 98.0 . . . . .
Check . . . . . . . . Untreated. . . . P 47 99 63 81 58 36 47 100. O . . . . .

The advantages of fumigating in a building of this ‘type are many,
and few of the most important ones may be mentioned here.

First: it

is cheaper because a large quantity of seed may be treated in a single
operation with the same dosage of carbon bisulphide. Second: the
building can be utilized for the storage of treated seed; it is particularly
adaptable for this purpose because it is Weevil-proof and treated seed
will not become reinfested. Third: the results obtained are more sat-
isfactory because leakage is reduced to a minimum. Temperature re-
mains nearer the normal, which is desirable to get the best penetration
of the fumes.

The results that were obtained from experiments conducted in this
fumigator are given in detail in Table 24. The different- stages in
which the weevil was exposed are represented by E for eggs, L for
larvae, and P for pupae.

The temperature and relative humidity were taken by a recording
hygro-thermograph placed on the floor beside the exposed cowpeas. It
should always be remembered that the treated cowpeas are subject to
reinfestation if they are not stored properly in weevil-proof containers
or bins.

86 TEXAS AGRICULTURAL EXPERIMENT STATION.

H eat.

It is a. long-established fact that heat is a satisfactory insecticide
where it can be employed economically. It is particularly applicable
to species oi’ insects attacking stored grains which are not seriously
affected by temperatures sufficiently high so as to destroy the insects
and not injure the texture or the germination of the seed.

Table 25.—Efl'ect of Heat on Egg Stage.

Temp. Exposure Age Per Cent Per_ Cent Temp. Exposure Age Per Cent Per Cent
(degrees)! (IIIIIL) (days) Emerged Killed (degrees) (m1n.) (days) ‘Emerged Killed
| < l
12O 5 1 85 15 12O 10 1 0 100
120 5 2 80 2O 12O 1O 2 65 35
120 5 3 9O 1O 12O 10 3 75 25
120 5 4 85 15 12O 10 4 60 4O
12O 5 5 85 15 12O 10 5 75 25
126 5 1 75 25 126 1O 1 0 lOO
126 5 2 95 5 126 1O 2 4O 60
126 5 3 6O 4O 126 1O 3 85 15
126 5 4 55 45 126 1O 4 60 4O
126 5 5 6O 4O 126 1O 5 4O 60
130 5 1 8O 20 130 10 1 1O 9O
130 5 2 3O 70 130 1O 2 45 55
130 5 3 9O 1O 13O 1O 3 65 35
130 5 4 7O 3O 130 1O 4 45 55
130 5 5 85 15 130 1O 5 35 65
136 5 1 25 75 136 1O 1 O 10O
136 5 2 25 75 136 1O 2 O lOO
136 5 3 10O 136 1O 3 5 95
136 5 4 55 45 136 10 4 2O 80
136 5 5 6 0 136 10 5 0 100
140 5 1 O lOO 140 1O 1 O 10O
140 5 2 O lOO 140 10 2 O lOO
140 5 3 5 5 140 1O 3 0 10O
140 5 4 O 1OO 140 1O 4 O 10O
140 5 5 5 95 140 1O 5 O 10O
146 5 1 O 10O 146 1O 1 O 10O
146 5 2 O 10O 146 1O 2 O 10O
146 5 3 O 10O 146 10 3 O 10O
146 5 4 O lOO 146 1O 4 O 10O
146 5 5 0 lOO 146 1O 5 O 10O
150 5 1 O lOO 15O 1O 1 O lOO
15O 5 2 O lOO 150 1O 2 0 lOO
15O 5 3 O lOO 15O 10 3 O 10O
15O 5 4 O 1OO 15O 1O 4 0 10O
150 5 5 O 1OO 15O 1O 5 _ O 10O

Effect of Heat on Larval Stage.

Temp. Exposure Age Per Cent Per_ Cent Temp. Exposure Age Per Cent Per Cent

(degrees) (m1n.) (days) Emerged Killed (degrees) (min.) (days) Emerged Killed
12O 5 1 85 15 12O 1O 1 90 1O
12O 5 2 9O 1O 12O 10 2 85 15
120 5 3 90 1O 12O 1O 3 9O 10
12O 5 4 7 3O 12O 1O 4 8O 2O
12O 5 5 10O O 12O 1O 5 10O O
12O 5 6 95 5 12O 1O 6 75 25
120 5 7 76 24 12O 1O 7 95 5
120 5 8 75 25 12O 1O 8 85 15
12O 5 9 95 a 12O 10 9 9O 1O
12O 5 1O 85 15 12O 1O 1O 8O 20
12O 5 over 1O 85 15 12O 1O over 1O 9O 1O
126 5 1 85 15 126 1O 1 15 85
126 5 2 7O 3O 126 1O 2 10O
126 5 3 8O 2O 126 1O 3 15 85
126 5 4 8O 2O 126 1O 4 80 2O
126 5 5 8O 20 126 1O 5 55 45
126 5 6 5 45 126 1O 6 ' 2O 8O
126 5 7 10O O 126 1O 7 6O 4O
126 5 8 95 5 126 1O 8 91 9
126 5 9 75 25 126 1O 9 85 15
126 5 1O 95 5 126 1O 1O 95

THE OOWPEA XVEEvIL. 87

Effect of Heat on Larval Stage-—C0ntinued.

1d an
Temp. Exposure Age Per Cent Per_ Cent Temp. Expqsure Age Per Cent Per_ Cent
(degrees) (min) (days) Emerged Kxlled (degrees) (m1n,) (days) Emerged Kllled
126 5 over 10 75 25 126 10 over 10 85 15
130 5 80 2O 130 10 1 O 100
130 5 85 15 130 10 2 25 75
130 5 3 75 25 130 10 3 0 1OO
130 5 4 8O 20 130 10 4 80 20
130 5 5 100 0 130 1O 5 1O 9O
130_ 5 6 85 15 130 10 6 0 100
130 5 7 85 15 130 1O 7 1O 9O
130 5 8 81 19 130 10 8 15 85
130 5 9 85 15 130 10 9 1O 9O
130 5 1O 80 20 130 1O 10 7O 3O
130 5 over 1O 100 O 130 1O over 1O 100 0
136 5 1 3O 7O 136 1O 1 0 100
136 5 2 2O 80 136 10 2 0 100
136 5 3 O 1OO 136 10 3 O 100
136 5 4 25 75 136 1O 4 0 100
136 5 5 5O 5O 136 10 5 O 100
136 5 6 67 33 136 1O 6 O lOO
136 5 7 70 30 136 10 7 O 100
136 5 8 50 5O 136 10 8 O 100
136 5 9 95 136 1O 9 0 100
136 5 1O 100 O 136 1O 1O 3Q’ 7O
136 5 over 1O 100 _ 136 1O over 10 75 25
140 5 1 O 100 14O 10 1 O 100
140 5 2 O 100 140 1O 2 O 100
140 5 3 5 95 140 1O 3 0 100
140 5 4 0 100 140 1O 4 O 100
140 5 5 O 100 140 10 5 O 100
140 5 6 0 100 140 1O 6 0 100
140 5 7 15 85 140 10 7 O 100
140 5 8 0 100 140 1O 8 O 100
140 5 9 10 9O 140 10 9 O 100
140 5 10 0 100 140 10 10 0 100
140 5 over 1O O 1OO 140 10 over 10 O 1()O
_146 5 1 O 100 146 10 1 O 100
146 5 2 0 100 146 1O 2 O 100
146 5 3 O lOO 146 1O 3 0 100
146 5 4 0 100 146 l0 4 O 100
146 5 5 0 100 146 10 5 0 100
146 5 6 5 95 146 10 6 O 100
146 5 7 0 100 146 10 7 0 100
146 5 8 0 100 146 1O 8 O 1OO
146 5 9 O 100 146 1O 9 O 100
146 5 1O 0 lOO 146 1O 1O 0 100
146 5 over 1O 0 100 146 10 over 1O O 100
150 5 1 0 100 150 10 1 O 100
150 5 2 O 100 150 1O 2 O 100
150 5 3 0 100 150 1O 3 O 100
150 5 4 0 100 150 1O 4 O 100
150 5 5 0 100 150 10 5 0 100
150 5 6 0 100 150 10 6 0 100
150 5 7 0 100 150 1O 7 0 100
150 5 8 0 100 150 10 8 O 100
150 5 9 0 100 150 10 9 0 100
150 5 1O O 100 150 1O 10 ' 0 100
150 5 over 10 O lOO 150 10 over 10 0 100
Effect of Heat on Pupal Stage.
l X I
Temp. ‘Expqsure Age \Per Cent Per_ Cent Temp. Expqsure Age Per Cent Per_ Cent
(degrees)i (m1n.) (days) ‘iEmerged Kllled (degrees) (m1n.) (days) Emergedi Kllled
i
, ‘ ‘

12o 5 1 l s5 15 120 10 1 90 i 10
120 5 2 100 O 120 10 2 85 15
120 5 3 95 5 120 10 3 90 10
120 5 4 100 O 120 1O 4 lOO 0
120 5 5 90 1O 120 10 5 100 0
120 5 over 5 100 1 0 120 10 over 5 85 ' 15
126 5 1 95 5 126 1O 1 95 5
126 5 2 90 1O 126 10 2 90 i 10
126 5 3 95 5 126 1O 3 86 14
12s 5 4 75 25 12s 10 4 s5 i 15
126 5 5 9O 1O 126 10 5 90. 1O
126 5 over 5 85 15 126 10 over 5 80 2O

88 TEXAS AGRICULTURAL EXPERIMENT STATION.

Effect of Heat on Pupal Stage-Continued.

Temp. Exposure Age Per Cent Per_Cent Temp. Exposure Age Per Cent Per Cent

(degrees) (min) (days) Emerged Killed (degrees) (m1n.) (days) Emerged Killed
130 5 1 100 0 130 10 1 90 10
130 5 2 90 1O 130 10 2 35 65
130 5 3 90 10 130 10 3 25 75
130 5 4 90 1O 130 10 4 80 20
130 5 5 85 15 130 l0 5 85 15
130 5 over 5 95 130 10 over 5 95 5
136 5 1 85 15 136 10 1 10 90
136 5 2 20 136 10 2 35 65
136 5 3 100 136 10 3 0 100
136 5 4 100 0 136 10 4 22 78
136 5 5 85 15 136 10 5 85 15
136 5 over 5 55 136 1O over 5 5 95
140 5 1 100 140 1O 1 O ~ 100
140 5 2 6O 4 140 10 2 O 100
140 5 3 35 65 140 10 3 0 100
140 5 4 5O 50 140 1O 4 O 100
140 5 5 0 100 140 1O 5 O 100
140 5 over 5 0 100 140 1O over 5 O 100
146 5 1 . 0 100 146 1O 1 0 100
146 5 2 5 146 l0 2 0 100
146 5 3 0 100 146 1O 3 O 100
146 5 4 0 100 146 1O 4 0 lOO
146 5 5 0 100 146 1O 5 0 100
146 5 over 5 0 100 146 1O over 5 0 100
150 5 1 O 100 150 10 1 O 100
150 5 2 0 100 150 1O 2 O 100
150 5 3 0 100 150 1O 3 O 100
150 5 4 O 100 150 1O 4 O 100
150 5 O 100 150 10 0 100
150 5 over 5 0 100 150 1O over 5 0 100

A series of experiments to determine the effect of heat on the various
stages of the cowpea weevil were conducted and the results are given
in detail in Table 25. All this work was done under laboratory con-
ditions and every possible precaution was taken to obtain results un-
influenced by other factors. A double-lined, two-hole Boss oven with
a tight-fitting base to prevent undue circulation of air, was used. The
bottom of the oven was lined with a sheet of asbestos to insure a more
uniform temperature from the source of heat applied beneath it. With
this arrangement the temperature within the oven could be held prac-
tically constant, at most varying not more than one degree. Only dry
heat was employed, the source being a gas flame. The temperatures
were recorded from a thermometer suspended on a level with the infested
cowpeas exposed in thin wire baskets.-

Cowpeas containing a normal moisture content were used in all
cases. It will be noted that only short time exposures were used with
a large variation in temperature. This was done for two reasons:
first, it was found by preliminary experiments, that a sufficiently high
temperature and short exposure could be employed to kill the weevil
without seriously affecting the germination of the seed; second. if heat
is to be employed for weevil control in a commercial way, it appears
very desirable to turn over the produce in as short time as possible.

i In order to determine the exact temperature which will destroy all
stages of the weevil, the eggs, larvae, and pupae at a difference in age
of 24 hours, were exposed. It was found that greater mortality occurred
in the younger material, the resistance to withstand heat increasing
with age. Referring to Table .25, it will be noted that no temperature
for either a five or ten minute exposure produced satisfactory results
under 140 degrees F. At a temperature of 140 degrees F. for ten

THE CowrEA WEEVIL. 89

minutes exposure the point at which nearly all weevil life is destroyed
is being approached; in fact, no emergence took place in any stage at
this temperature and exposure. However, a temperature of 146 degrees
F. for five minutes’ exposure did not destroy all the developing weevils,
but when the exposure was increased to ten minutes all the weevils in
each stage were destroyed. It should be remembered that since these
experiments were conducted under most favorable conditions, which
might not be readily duplicated in a practical way, due allowance must
be made for variations in results obtained. The germination of the
seed is not affected by this temperature and it is advisable to increase
the exposure to twenty or thirty minutes in all cases where the tempera-
ture cannot be held constant and large quantities of cowpeas are being
treated.
Efiect of Heat 0n Germination.

Uninfested cowpeas of the same lot used in the experiments on heat
control, were exposed in a similar man.ner for five and ten minutes’
exposures to temperatures ranging from 120 to 200 degrees F. In
order to obtain complete information relative to the effect of heat on
the seed, they were planted in» the field and notes were taken on the
character of plants produced, While the per cent. of germination was
obtained. The results are given in Table 26. It will be noted that the
per cent. of germination did not seem to be seriously affected at any
temperature under 190 degrees F, though weak plants occurred con-
sistently from exposure to a temperature of 1'? 0 degrees F. Everything
below 150 degrees F. with four exceptions produced normal and vigor-
ous plants.

Table 26.—Effect of Heat on Germination.

Temperature, Exposure, Number Number Per Cent
Degrees Min. Planted Germ. Strong Weak Germ.
120 . . . . . . . . . . . . . . . . . 5 2O 2O 2O O lOO

120 . . . . . . . . . . . . . . . .. 10 20 19 19 0 95

126 . . . . . . . . . . . . . . . .. 20 18 18 0 90

126 . . . . . . . . . . . . . . . .. 10 20 20 20 0 100

130 . . . . . . . . . . . . . . . .. 20 20 20 0 100

130 . . . . . . . . . . . . . . . . . 1O 2O 2O 19 1 100

136 . . . . . . . . . . . . . . . .. 20 18 18 0 90

136 . . . . . . . . . . . . . . . .. 10 20 19 18 1 95

140 . . . . . . . . . . . . . . . .. 20 20 20 0 100

14O . . . . . . . . . . . . . . . . . 1O 2O 18 17 1 9O

146 . . . . . . . . . . . . . . . .. 20 19 19 1 95

146 . . . . . . . . . . . . . . . .. 10 20 20 20 0 100

150 . . . . . . . . . . . . . . . . . 2O 19 19 O 95

150 . . . . . . . . . . . . . . . . . 1O 2O 2O 2O O IOO

156 . . . . . . . . . . . . . . . .. 20 20 18 2 100

156 . . . . . . . . . . . . . . . .. 10 20 20 19 1 100

160 . . . . . . . . . . . . . . . .. 20 20 20 0 100

160 . . . . . . . . . . . . . . . .. 10 20 19 19 0 95

166 . . . . . . . . . . . . . . . .. 20 19 18 1 95

166 . . . . . . . . . . . . . . . .. 10 20 18 18 0 90

170 . . . . . . . . . . . . . . . . . 5 2O 2O 17 3 1OO

170 . . . . . . . . . . . . . . . .. 10 20 17 15 2 85

180 . . . . . . . . . . . . . . . .. 5 20 19 17 2 95

180 . . . . . . . . . . . . . . . .. 10 20 18 16 2 90

186 . . . . . . . . . . . . . . . .. 5 20 19 17 2 95

186 . . . . . . . . . . . . . . . .. 10 20 18 16 2 90

190 . . . . . . . . . . . . . . . .. 5 20 18 15 3 90

190 . . . . . . . . . . . . . . . .. 10 20 17 15 2 85

196 . . . . . . . . . . . . . . . .. 5 20 19 16 3 95

I96 . . . . . . . . . . . . . . . .. 10 20 16 14 2 80

. . . . . . . . . . . . . . . .. 5 20 13 8 5 65

200 . . . . . . . . . . . . . . . .. 10 20 13 8 5 65

9O TEXAS AGRICULTURAL EXPERIMENT STATIoN.

SUMMARY.

The most common species of Weevil infesting cowpeas in Texas is
Bruchus quadrvlnzaculcttus Fabr. It is found in all localities of this
State where cowpeas are grown. The climatic conditions of Texas are
especially favorable for the development of this insect. All varieties-
of cowpeas grown in this locality are subject to attack, and no preference
is shown by the Weevil to any particular variety. The annual loss in
Texas to the cowpea crop, resulting from this insect, is very great.

_ Under favorable conditions the life cycle from egg deposition to-
emergence of the adult may be completed in less than three weeks. The
weevil is very prolific. An average of 106 eggs have been produced by
females during the warm season. Temperature has a positive influence
on the rate of oviposition and the length of the various stages of the
Weevil. In stored seed breeding is practically continuous throughout
the year. Most WQQVIIS undoubtedly hibernate in stored seed. Nine
generations of weevils occur in a year at College Station.

Three .natural enemies of the immature stages of the weevil were
found: a predacious mite, a chalcid, and an egg parasite. The weevil,
however, is not sufliciently checked by its natural enemies, and remedial
and artificial control measures must be employed. Proper harvesting
will greatly reduce the initial infestation of the field. To prevent seed
from becoming reinfested it must be stored in tight bins or containers.
The weevil can be destroyed in any stage by heating the infested seed
to a temperature of 1~3l~6 degrees F. for an exposure of fifteen minutes,
which will not affect the germination of the seed. Fumigation with
carbon bisulphide is an effective means of destroying the cowpea weevil
and, used at the rate of four pounds for a thousand cubic feet of space
with. a 24-hour exposure, it will kill the insect in all of its stages.
Fumigated and “processed” or heated seed is always subject‘ to rein—
festation by the weevil.

LITERATURE CITED.

(1) 1792. Fabricus, Ento. Syst. I, 2, p. 371. Original description

with habitat.

(2) 1795. Olivier, Historie Naturelle des Insects, IV, '79, p. 19.
Habitat.

(3) 1801. Fabricus, Syst. El., II, p. 398. Description.

(4) 1824. Say, Entomology, I, p. 259. Specimens taken at New
Orleans. Habitat includes Santa Cruz.

(5) ' 1853. Le Conte, Revision of Say Entomology, I, p. 259. Crit-
icizes systematic position of species.

(6) 1872. Horn, Trans. Am. Ent. Soc, IV, p. 318. ,Technical
description of species.

('7) 1885._ Riley and Howard, Insect Life, V, p. 165. Infested

' table beans from Texas.

(8) 1893. Riley, C. V., Insect Life, VI, 3, p. 220. In beans from
Brazil and Venezuela at V\7orld’s Fair.

(9) 1893. Beckwith, M. H., Del. Bull. 21, p. 10. In peas from
North Carolina.

THE CoWPEA WVEEVIL. 91

(10) 1893. Slingerland, M. V ., Psyche, VI, p. 447. Introduced in
peas from the South.

(11) 1894. Hamilton, John, Trans. Am. Ent. Soc., XXI, p. 400.
Records species.

(12) 1895. Osborn and Mally, Ia. Sta. Bull. 32, p. 161. Descrip-
tion of stages. _

(13) 1896. Chittenden, F. H., Bur. Ent. Bull..8 n. s., p. 27. Dis-
tribution.

BIBLIOGRAPHY.

Ashmead, Wm. H. 1894. Notes on Insects Found in Mississippi.
Ins. Life, vol. V.II, No. 3, p. 246. Found in cotton blooms.

Bandi, F. 1890. Dent. Ent. Zeit., p. 338. Records localities.

Beckwith, M. H. 1893. Del. Bull. 21, p. 10. Weevils in North Caro-
lina cowpeas determine-d to be B. quadrimaculatus. Remedy is
carbon bisulphide.

Blatchley, W. S. 1910. Coleoptera o1’ Indiana, p. 1237. Listed.

Chittenden, F. H. 1896. Insects Injurious to Vegetables, pp. 105-107.
Description, occurrence, habits, life history. Effect of carbon
bisulphide on larvae and pupae. Effect on germination.

Chittenden, F. H. 1897. Some Little-known Insects Affecting Stored
Vegetable Products, U. S. D. A. Div. Ent. Bull. 8 (n. s.), p. 27.
Occurrence, distribution, and parasitic enemies.

Chittenden, F. H. 1898. Insects Injurious to Beans. U. S. D. A.
Yearbook, 1898, p. 245. Distribution, history, and remedy are

iven.

Chittgenden, F. H. 1898. Yearbook U. S. D. A._, 1898, p. 247. Pre-
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Chittenden, F. H. 1912. The Cowpea Weevil. U. S. D. A. Bur.
Ent. Bull. 96, pt. 6, pp. 83-94. Species just mentioned.

Currie, R. P. 1905. Cat. of the Exhibit of Eco. Ent. at the Lewis &
Clark Centennial Exposition. U.  D. A. Bur. Ent. Bull. 53, p.
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Duvel, J. W. F. 1905.’ Cold Storage for Cowpeas. U. S. D. A. Bur.
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Fabricus. 1792. 96 Bastrichus Ento. Syst, vol. I, pt. 2, p. 371. De-
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Fabricus. 1801. Brychus. Syst. El., II, p. 398. Description given.
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(1914), 1, p. 149. Experiments on CoWpea Weevil. '
Hamilton, John, 1894. Distribution of Coleoptera. Trans. Am. Ent.

Soc., XXI, p. 400. Records B. quadrimaculatus.

Horn, Geo. H. 1872. Revision of the Bruchidac of the U. S. Trans.
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scutellaris and B. quadrimaculatus.

Krall, J. A. 1914. The Cowpea Weevil. Okla. Sta. Cir. 31, p. 8.
Notes on controlling the coWpea Weevil. .

Le Conte, J. L. 1853. Revision of Say Entomology, I, p. 259.
Criticizes systematic position of species. _

O’Kane, Wj C. 1912. Injurious Insects, p. 366. Habits and Life
History. Remedy given.

92 ‘Fnxxs AGRICULTURAL EXPERIMENT STATION.

Olivier. 1795. Historic. N aturelle des Insects, vol. IV, No. '79, p. 19.
Distribution. v

Osborn, H., and Mally, C. W. 1895. Entomological Work for 1895.
Iowa Sta. Bull. 32, pp. 161-407, pl. 1, fig. II. Description. Ex-
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Pettit, R. H. 1910. Mich. Exp. Sta. Bull. 258. Injury and remedy
are given.

Price, R. H. 1894. Insects Injurious to Stored Grains. Texas Bull.
31, p. 466. Occurrence, injury and tests of preventives.

Quaintance, A. L. 1896. Insects Injurious to Stored Grain. Fla.
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habits.

Riley and Howard. 1893. Food-plants of N. Am. Species of Bruchus.
Insect Life, vol. V, p. 165. Notes on species.

Riley, C. V. 1894. Insects Which Occurred in Grain and Other
Stored Vegetable Products at the World’s Fair. Insect Life, vol.
VI, No. 3, p. 220. Common in the Southern States. In beans
from Brazil and Venezuela.

Sanborn, C. E. 1914. Garden and Crop Pests. Okla. Sta. Bull. 100,
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Sanderson, D. W. 1912. Insect Pests of F. O. & G., p. 312. De-
scription, occurence, life history, and remedial measures.

Say, Thos. 1859. American Entomology, vol. I, p. 259. Distribution.

Skaife, S. H. 1918. Pea and Bean Weevils, Bull. 12, Union of S. A.
Dept. of Agr. Brief account.

Slingerland, M. V. 1893. B. quadrimaculatus Fabn, Psyche, vol. VI,
p. 447. Occurrence, and life history are given.

Steadman, J. M. 1895. Insects Injurious to Stored Grain. Ala.
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Titus and Pratt. 1904. Cat. of Exhibit of Eco. Ent. at the La. Ex-
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Urich, F. W. 1918. The Black-eye Pea Weevil. Bull. Dept. Agr.,
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