192 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



the beans at this point. No larvse entered the beans. Larva in the 

 act of chewing their entrance holes have their bodies arched against 

 some surface as if braced against it. I do not think the larvae secure 

 any aid from the walls of the egg shell but evidently they do require 

 a position where they can brace themselves and so exert their muscular 

 efforts to the best advantage in order to penetrate the hard coating of 

 the bean. They take advantage of any break in the surface of the 

 bean and also the entrance hole left by another. Several larvae may 

 enter through the same hole, each branching off into a new channel 

 soon after entering and taking up a feeding area of its own. The 

 entrance hole has a diameter of about .232 mm. and is filled with 

 fine white powder, some of which may be scattered around on the 

 surface. The legs are lost soon after entering. The number of days 

 required for the larva to become full grown has varied from 27 to 54. 



The Pupa 



The pupal cell, lined in white, is located adjacent to the surface of 

 the bean with some of the testa chewed away, so that only a very thin 

 translucent membrane separates the insect from the outside world. 

 This area becomes dark when the pupa beneath changes into the adult. 

 The snowy white pupa gradually darkens, the eyes, mouthparts, and 

 wings being the first to change. The time elapsing from the forma- 

 tion of the pupa to the emergence of the adult has varied from 8 to 

 20 days. 



Doctor Lintner states that the lid of the exit hole is not formed by 

 the larva but by the beetle and that it is not formed at the semi- 

 transparent spot made by the larva "but removed a little therefrom, 

 perhaps slightly more than the cell's length." From my observations 

 I find that the lid is cut out of the translucent area made by the larva. 

 The adult cuts around and through the circumference of the lid so 

 that it can be pushed open or away. Thus the larva and the adult 

 each have their share in forming the lid of the exit hole. 



Adult 



The adults may mate almost immediately after emerging and the 

 female may even lay eggs within 24 hours. Females kept away from 

 beans will refrain from laying eggs for several days while those with 

 beans will lay soon after mating. The egg-laying period varied from 

 3 to 18 days; the average for 37 females was 8 days. The number of 

 eggs laid by individual females varied from 5 to 75 with an average of 

 45 eggs. The length of life of the adult in stored beans is not long, 

 usually about 10 or 12 days if they are allowed to mate and oviposit 

 normally. I think that the female lives the longer. There is a wide 



