298 
Journal of Agricultural Research 
Vol. XXIX, No. a 
that in the great majority of instances 
the first is true. The second does not 
appear plausible, but the third may 
offer a solution for very light infesta¬ 
tions in some cases and forms the 
basis for the experiments herein de¬ 
scribed. 
SCOPE OF THE EXPERIMENTS 
The present paper gives a summary 
of results of experiments conducted 
by the writers in 1923 at Alhambra, 
Calif. Four different sets of experi¬ 
ments beginning May 7 were carried 
on, three simultaneously and one later. 
Red Ripper cowpeas in glass vials 3 
inches by % inch in size, provided with 
cork stoppers, were used throughout the 
experiments. 
In experiment one, 100 pairs of newly 
emerged weevils were placed in vials, 
each of which contained 6 cowpeas. 
The vials were numbered consecutively 
from 1 to 100. Into each of the vials 
numbered 1, 5, 9, and every fourth 
vial to and including 97, was put a drop 
of water. Into each vial numbered 2, 
6,10, and every fourth vial to and includ¬ 
ing 98, was put a drop of honey. Vials, 
3, 7, 11, etc., to and including 99, were 
each given a drop of saturated sugar 
water, while the remaining vials, 4, 8, 
12, etc., contained only cowpeas and 
weevils, used as controls. All were 
examined daily, the cowpeas being 
replaced by others, the eggs recorded, 
and the water, sugar water, and honey 
being replenished as needed. Because 
of evaporation the water needed to be 
replenished daily and the honey and 
sugar solution less frequently. The 
date when the male or female died was 
also recorded. 
Experiments two and three were sim¬ 
ilar in arrangement except that in experi¬ 
ment two only one male was placed in 
each vial, while in experiment three 
only one female was placed in each vial. 
Some of the females were known to 
have mated and others had had an 
opportunity to mate. 
In experiment four only 24 females 
were taken, none of which had had 
an opportunity to mate. They were 
numbered and given food in the same 
manner as the others, there being only 
six individuals in each of the groups 
having water, honey, sugar water, or 
nothing, while in each of the other 
experiments there were 25 in each 
group. 
The experiments were intended pri¬ 
marily to determine whether or not 
the presence of certain foods would aid 
the adult weevils to live longer than 
they ordinarily lived under normal 
warehouse conditions; in other words, 
to try to determine if food would sup¬ 
port these short-lived insects while 
their host plants were becoming suffi¬ 
ciently developed for oviposition to 
occur. Whether adult weevils will live 
3 months or less than 20 days is a vital 
question when trying to control them 
in the field. Together with the length 
of life as influenced by different kinds 
of foods this summary deals with the 
length of life as it is influenced by 
mating and reproduction, the number 
of eggs and their viability as influenced 
by the food and age of the parent 
female, and the asexual production of 
eggs. These data are related to the 
rate of increase as well as to the control 
of the weevils. It is thought that they 
will contribute something toward a 
more thorough knowledge of a very 
vital part of the life of this destructive 
and widespread species. 
While the principal food of Bruchus 
quadrimaculatus in California is the 
black-eyed cowpea, it apparently breeds 
as freely in any other variety of cowpeas 
(Vigna sinesis ) which may be available. 
Because the eggs can be seen more 
readily on Red Ripper cowpeas than 
on Black-eyes, the former were used 
throughout the experiments. 
RESULTS OF EXPERIMENT 1 
Table I presents the results of ex¬ 
periment 1. An examination shows 
readily that there was not only a great 
difference between the average length 
of life of the weevils receiving liquid 
and that of those receiving none, but 
it also shows that there was a corre¬ 
sponding difference in the number of 
eggs laid. The males and females 
without food lived an average of 17.48 
and 17.72 days, respectively, with 
maxima of 22 and 27 days. Those 
given water lived an average of 10 
days longer, or 27.24 days, with a 
maximum of 35 days for the males and 
51 for the females. Those fed on 
honey averaged 27.76 days, or only a 
fraction of a day longer than those 
given water, but the maximum age 
for males was 60 and for females 44* 
Those fed on sugar water lived an 
average of 36.84 and 30.68 days for 
males and females, respectively, with 
maxima of 56 and 54 days. For both 
sexes the average length of life in each 
group having liquid was greater than 
the maximum for either sex without 
food; while the average life of the 
males receiving sugar water was more 
than twice that of those without food. 
Three insects, representing both sexes, 
lived twice as long as any weevil with- 
