310 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



ings as arc caused by its drying and splitting (Fig. 224, b, c). In 

 shelled beans the eggs are placed loosely among them or in the 

 exit holes of the beetles. The young larva hatching from the egg 

 has long, slender legs, but with the first molt these are lost and 

 when full grown it is a fat grub as shown in Fig. 223, b. The pupal 

 stage is passed in an oval cell made by the larva within the bean. 

 Experiments have shown that the eggs hatch in from five days in 

 the hottest to twenty days in cooler weather; the larval stage 

 requires eleven to forty-two days, and the pupal stage five to eigh- 



FIG. 224. The bean-weevil; a, side view of beetle; b, section of bean pod 

 showing slit for deposition of egg; c, part of inside of pod showing egg- 

 mass inserted through slit all enlarged. (After Riley and Chittenden, 

 U. S. Dept. Agr.) 



teen days. Thus the whole life cycle will extend over a period of 

 from twenty-one to eighty days, depending upon the season and 

 locality. Probably a' out six generations occur annually in the 

 District of Columbia, and a less number further north. 



" Unlike the pea-weevil, a large number of individuals will 

 develop in a bean, as many as twenty-eight having beenf ound 

 within a single seed. It will thus be readily seen that the first out- 

 door generation or any single indoor generation is capable of 

 exhausting seed and completely ruining it for food or planting or 

 any other practical purpose, except perhaps as hog feed." 



" The beetles begin to issue from beans in the field in a climate 



