THE BKOAD-BEAN WEEVIL. 
71 
of the tissue is consumed and the germinating power reduced nearly 
one-half, while the growing power of the plant is also diminished, and 
there is, moreover, in the case of a plant growing, a much lessened 
yield of seed, which is also apt to he imperfect. 
The method of attack is in brief as follows : 
The female weevil begins to deposit her eggs on the young seed 
vessel in the blossom before and after the former has developed into 
a pod. Here the eggs hatch and the larvae penetrate into the growing 
seeds, each gnawing a gallery for 
itself, which it lengthens from time 
to time, as needed. (See fig. 17.) 
When full grown, the larva trans- 
forms to pupa within the accumu- 
lated frass and develops later into 
the beetle stage. This develop- 
ment may take place at different 
periods, the beetles being found 
afield in some regions as early as 
February and until May, some 
leaving the seed as soon as fully 
developed and others remaining 
until they have cut through the 
skin which remains over the cell 
while the insect is in the larval and 
pupal stages. When the beetle 
wishes to emerge it gnaws around 
this circular piece of skin and forces 
its way through. 
As is the case with the pea weevil, 
this species hibernates in the adult 
condition, and a single generation 
develops each year. Pupae have 
been observed as early as August 
3, in California, and the proba- 
bilities are that in most seasons the beetles will have developed by 
the middle of August, or a little later; hence, as they are seen in 
the field toward the end of March and first of April, it can be deduced 
that the life of the beetle extends from about the middle of August 
to the middle of April and later — a period of 8 or 9 months. 
The separate periods for the egg, larval, and pupal stages do not 
appear to have been observed. 
Fig. 17. — Broad beans split to show ravages 
made by larvae of the broad-bean weevil 
above, and by larvae and adults below, the 
latter leaving large pupal cases at the ends 
of the beans. (Original.) 
