282 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



form to the common brown-gray weevils which infest white beans. 

 In the South its attacks are so serious that it is almost impossible 

 to secure a crop uninfested, so that most of the beans both for 

 seed and consumption come from the North. Not until 1870 did 

 injury by this insect attract attention in the United States, but 

 now it occurs throughout our borders and is practically cosmopol- 

 itan in its distribution. It is probably a native of Central or 

 South America. 



The adult weevil is about one-eighth of an inch long and is cov- 

 ered with a fine 

 brown-gray or olive 

 pubescence, giving it 

 that color, while the 

 wing-covers are mot- 

 tled as shown in Fig. 

 240, a. It may be 

 distinguished from 

 the pea-weevil by its 

 longer thorax and by 

 the two small teeth 

 next to the large 

 tooth at the tip of 

 FIG. 241. The bean-weevil; a, side view of beetle; the thighs. 



6, section of bean pod showing slit for deposition Life History In 



of egg; c, part of inside of pod showing egg-mass J ( y- 



inserted through slit all enlarged. (After Riley the field the eggs are 

 and Chittenden, U. S. Dept. Agr.) laid upon or are in _ 



serted in the bean-pod through holes made by the female or such 

 openings as are caused by its drying and splitting (Fig. 241, 6, 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. 240, 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- 

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

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



