170 [January, 



the pseudo-pupcD were not unfrequently met with. The thought at 

 once occurred to me that locust eggs might be the proper food for 

 these blister-beetle larvae, and it was encouraged by the fact that the 

 Meloids abound most in those dry western regions where the Acridiidce 

 most prevail, and by a pretty distinct recollection, which my notes 

 support, that the years when the Vesicants were most injurious to 

 potatoes had been preceded by dry falls, during which there had been 

 much locust injury and, necessarily, unusual locust increase. The 

 suspicion thus raised, that these blister-beetles preyed in the preparatory 

 states upon locust eggs, was confirmed last spring by finding the larvae 

 of different ages within the egg-pods and devouring the eggs of 

 Caloptenus spretus. 



Prom such larvae preying on the eggs of spretus, I have reared 

 the unicolorous form of Epicauta cinerea (Forster), or the Margined 

 Blister-beetle; the Epicauta pennsyJvanica (DeGeer), or the Black 

 Blister-beetle ; the Macrohasis unicolor (Kirby), or the Ash-gray 

 Blister-beetle ; and the form of it described as murina by Le Conte, or 

 the Black-rat Blister-beetle. 



Since then I have found it very easy to trace the larval habits and 

 development of the two more common potato-feeding species around 

 St. Louis, viz , the Striped Blister-beetle {Epicanta viitata, Fabr.) and 

 the Margined Blister-beetle {mm^ginata, Fabr.) just alluded to. 



Careful examination of locust-eggs in the vicinity of potato 

 fields frequented by these beetles, shows a varying proportion of the 

 egg-pods affected, and in some locations nearly every pod of the 

 Differential Locust {Caloptenus differential is) will contain the Epicatif a 

 larva. The eggs of this locust are laid in large masses of 70 to about 

 100. The pod is but slightly bent, rather compact outside, while the 

 eggs are irregularly arranged, and capped with but a shallow covering 

 of mucous matter. It is the egg-pod of this species which the larvae 

 of the two Blister-beetles in question prefer ; for, while they will feed 

 upon those of other species in confinement, I have so far found none 

 in the deeper-necked, narrower, more compact egg-pods cither of 

 Caloptenus femur -ruhr urn, G. Atlantis,. or (Edipoda sulphurea, in which 

 the eggs are regularly and quadrilinearly arranged as in those of C. 

 spretus. Not only have I found a large proportion of the egg-pods of 

 C. differentialis naturally infested with these Epicauta larvae, but I 

 have succeeded in hatching and rearing numbers in-doors, and have 

 them even at this writing (Oct. 30th) by hundreds, in all stages from 

 the first larva to the pseudo-pupa. 



From July till the middle of Octoberjithe eggs are being laid in 



