34 



THE MONTHLY BULLETIN. 



LIFE -HISTORY. 



The eggs are laid upon the pods while the latter are quite small. 

 The larv£e, shortly after hatching, bore into the pods and into the beans. 

 The hole in the growing bean soon closes np with the larva inside and 



Fig. 17. 



-The pod of the Guamuchile bean. 

 reduced. (Original.) 



Slightly 



continuing to feed. Just before going into the pupal stage the larva 

 eats its way up to the outer membrane of the bean, leaving just a thin 

 circular pellicle in such shape that the adult can easily push it out when 

 emerging. 



The larva is a white grub, one-fifth of an inch long. 



The pupa is that of a typical Bruchid. 



CONTROL. 



Fumigation with carbon bisulphide is generally recognized as the 

 best treatment for the infested beans. It seems impossible to prevent 

 the oviposition of eggs in the pods while in the field. It may be sug- 

 gested that the following method will help to abate the nuisance : Dis- 

 infect all beans before planting in a closed container, using one pound 

 to 1,000 cubic feet of space. Do not seed in soil which had beans on it 

 the previous year. 



Unless the weevils are destroyed very soon after the crop is gathered, 

 they riddle the beans and finally leave practically nothing but the 

 covering. 



