86 



Messrs. Forbes, Slingerlancl, and Smith were of the opinion that none 

 of the -.Egeriaus were attracted by electric lights. 

 The next paper presented was on — 



THE BEAN WEEVIL. 



By M. V. Slixgerland, Ithaca, N. Y. 



The Bean Weevil has recently received considerable attention from 

 entomological writers. Its habit of breeding freely in dry beans has 

 been strongly emphasized, and several interesting features of the first 

 larval stage are noted. Its life history has been regarded as similar to 

 that of the Pea Weevil, Bruchus pisi, the egg being laid upon the outside 

 of the pod, the young larva hatching therefrom, boring through the 

 pod and entering the seed, the adults appearing later through a cir- 

 cular opening cut in the shell. The Bean Weevil differs, however, in 

 that more than one may develop in a single seed, and that the Pea 

 Weevil does not appear to breed in dry peas. 



No one seems to have seen the eggs of the Bean Weevil laid upon the 

 pod, however, and by confining the beetles in cages with growing beans 

 I have found that this is not their normal method of oviposition. The 

 eggs are laid within the cavity of the pod. This is accomi)lished in the 

 following manner: The beetle first gnaws a narrow slit about 1 mm. in 

 length through the ventral suture of the pod. It then forces its long, 

 curved, semichitirous, telescopic ovipositor through the slit and de- 

 posits its eggs in a cluster inside the pod. The beetles oviposited only 

 on the larger green pods. I have not had an opportunity to study the 

 ovipositor of the Pea Weevil, which would prove interesting in this 

 connection. 



After emerging from dry beans, the beetles soon copulate and ovi- 

 posit, and die in a few days; but when placed in a cage on the growing 

 plant they remained alive feeding upon the parenchyma of the leaves 

 for a mouth or more. Should it be found that they thus feed in the 

 spring awaiting the growth of the pods, remedies for combatting the 

 pest in the field will suggest themselves. 



I have reared several broods of the weevils in dry beans and find 

 that, even when the experiment was conducted in the slightly varying 

 temperature of an office, the season noticeably affected their develop- 

 ment. For instance, when the eggs were laid in March adults issued 

 in about eighty days, while in July beetles emerged from beans upon 

 which eggs had been laid only forty-eight days before. 



I find the duration of the egg stage in dry beans in summer to be 

 about twelve days ; of the larval stage twenty-four days ; of the pupal 

 stage, eleven days. During the colder months the stages were passed 

 in twenty, forty-two, and eighteen days, respectively. 



