PSYCHE. 



NOTES FROM THE CORNELL INSECTARY. 

 III.— SOME OBSERVATIONS UPON TWO SPECIES OF BRUCHUS. 



BY M. V. SLINGERLAND, CORNELL UNIVERSITY, ITHACA, N. Y. 



Bruchus obtectus Say. 



Although this cosmopolitan insect 

 has been known in this country for over 

 sixty years, and has been recognized as 

 a common and destructive pest for more 

 than a quarter of a century, still it is 

 only within the past year that several 

 interesting phases of its life history 

 have been discovered. During the past 

 two years not less than forty pages of 

 our entomological reports and maga- 

 zines have been devoted to discussing 

 this pest. And even now there is need 

 of a further study of the species. For 

 instance, we know but little of its habits 

 in the field and hence are not able to 

 suggest any treatment for preventing its 

 ravages until after the deadly work of 

 the larva has begun in the seed. 



The name of this insect has been in 

 an unsettled condition for many years, 

 but obtectus Say apparently has priority 

 and is now generally adopted. In 1879 

 M. Maurice Girard (Jour. soc. centr. 

 hort. France, pp. 95-99) said that 

 "several entomologists believe that it 

 has been described under different 



names which come under the synonomy 

 of B. obtectus Say. It is the B. irre- 

 sechis Schonherr." Dr. Riley has tried 

 for many years to establish his name 

 fabae, but has recently (Ins. life, v, 27, 

 1892) reached a similar conclusion as 

 M. Girard, placing irresectus, fabae, 

 and other names under the synonomy of 

 obtectus Say. Dr. Horn writes me 

 recently that Dr. Riley is probably cor- 

 rect in his change of the name obsotetzts 

 to obtectus. 



Previous to June, 1S92, I had sup- 

 posed, and it had always been so 

 recorded, that the beetles laid their eggs 

 upon the outside of the bean-pod, the 

 young larva hatching therefrom boring 

 through the pod and entering the seed. 

 In May, 1892, I confined several beetles 

 in cages containing growing bean plants. 

 The beetles fed upon the surfaces of the 

 leaves until the pods were nearly full 

 grown but still green. I frequently saw- 

 beetles at work gnawing a narrow slit in 

 the ventral suture of the pod, and trying 

 it from time to time with their oviposi- 

 tor; several beetles would work on the 

 same slit, one driving another away and 



