THE COWPEA WEEVIL. 91 
upon the season, temperature, and other circumstances, and burrow 
into the pods to the developing seed, which they penetrate. In 
two or three weeks in midsummer weather, and in about two months 
in cooler weather, they attain full growth, when they present much 
the same appearance as the larve of other bean and pea weevils. 
The pupal state lasts from about four or five days in warm weather 
to considerably longer in cooler weather, whereupon the beetle form 
is assumed. The beetle gnaws its way out of the seed in the same 
manner as do the related species, by cutting a round flap through the 
skin of the pod. The first brood which develops in the field attains 
maturity by about the third week of September, or perhaps earlier, 
if we may judge by the appearance of the exit holes in the pods 
and the further fact that certain varieties of cowpea mature sooner 
than this. 
The beetles continue to develop in the stored seed for several 
generations, in fact until the seed becomes completely ruined for 
any practical purpose and unfit even for the sustenance of this 
insect; then decomposition sets in, inviting swarms of mites, and 
the beetles are forced to other quarters in their struggle for existence. 
In a fairly warm indoor temperature six or seven broods probably 
develop annually in a latitude like that of Washington, D. C. 
LITERATURE. 
In 1758, Linneus described this species, giving it its specific name 
from its known habitat at that time. On this head he wrote “ Habitat 
in Pisis omnis generis, e China allatis,’ showing that its injurious 
habit was known even at that early date, and that China was evi- 
dently the original home of this species. 
Tt will not be necessary to mention all of the references cited in 
the bibliography which will follow. 
In 1890 Dr. J. A. Lintner® published the first general account of 
this species. His published life history was a surmise, and later 
proved to be incorrect by his own statement. In 1896 Messrs. Osborn 
and Mally?* gave a more extended account of this species, based on 
its occurrence in Iowa, with notes on its life history, effects of fumi- 
gation with carbon bisulphid, and results of germination tests to de- 
termine the effect of bisulphid of carbon on the fumigated seed. The 
difference in comparison with a check lot showed practically no in- 
jury by this form of treatment, the final conclusion being reached 
that “the germinating power of the seeds was not impaired.” Three 
new food plants were mentioned—green field peas, horse-beans, and 
soy beans. Unfortunately this species was confused with the related 
four-spotted bean weevil, both being present in the seeds under ob- 
servation. The following year, 1897, the writer’ brought together a 
summarized account of this species based largely on personal inves- 
