Weevils in Beans and Peas. 15 
to the temperature. It requires 21 
to 80 days at least, according to the 
season and locality, for a generation 
of the bean weevil to develop. In 
the District of Columbia there may 
be as many as six generations a year. 
The warmer the climate the greater 
the number of generations and the 
consequent damage done by the 
grubs. 
In a climate similar to that of the 
District of Columbia and adjacent 
parts of Maryland and Virginia 
adults of the first gencration started 
in the field begin to emerge as early 
Fie. 13.—-Cowpea weevil: a, Adult male; 
b, eggs; c, postembryonic larva; d, front 
view of head of same; e, thoracic leg of 
same, @, Much enlarged; vb—e, more en- 
larged. (Chittenden.) 
as October If the fall is early and 
the seeds are stored in a cold place 
no adults may emerge before the fol- 
lowing spring. If seeds are stored 
in a warm place adults may emerge 
at any time during the winter. 
After emergence in storage the adult 
females lay eggs either on the beans 
or on the sides of the receptacles in 
which the seeds are stored. 
THE COWPEA WEEVIL.” 
The cowpea weevil (Fig. 13) is a 
foreign species first described from 
China but now widely distributed in 
dried seeds over the entire United 
States. It has been recorded from 
every continent-and is likely to be 
Fic. 14.—Different varieties of cow- 
peas showing infestation by cow- 
pea weevil. Seed about natural 
size; the white specks on the seeds 
are the eggs of the weevil. 
Jf! 2 2 2 ee ree eee 
10 Bruchus chinensis Linnaeus. 
