58 



on the species actually engag-ed therein. Material kindly placed at m}^ 

 disposal by Doctor Fletcher has shown that it was (Iscinl.s carhonaria 

 Loew that committed the depredations in Canada. Professor Washburn 

 was less fortunate, though he did all that was possible for him to do to 

 aid me, and sent specimens that, judging- from the labels attached, had 

 been reared by Doctor Lugger, ])ut whether from wheat or not it is 

 impossible to determine, as nothing could be found that would throw 

 any light upon this point. The specimens sent me from Minnesota by 

 Professor Washlnirn comprised two species, O. soror and O. do7'sata 

 Loew, the former having been supposed b}^ Doctor Lugger to have been 

 responsible for the injuries to wheat in Minnesota in 1892, while the 

 latter was reared b}^ me from wheat plants in Ohio in the fall of 1897, 

 thus indicating that both might have been involved in the Minnesota 

 trouble. Assuming that Doctor Lugger had sufficient grounds for 

 holding Oscinis soror responsible for the damage in his State at the 

 time stated, I have so considered it here, but have thought proper to 

 indicate the uncertainties surrounding this conclusion. Not being able 

 to secure any material whatever from Professor Garman, I am forced 

 to reluctantlv place the blame for the outbreak in the wheat fields in 

 Kentucky in 1889 upon Oscinis soror, but with a strong suspicion that 

 it was really Oscinis carhonaria that was responsible for the trouble. 

 I have applied Doctor Lugger's descriptions of the larva and pupa to 

 this species as being the best that can be done with our present knowl- 

 edge of these insects, but subject to revision, as future investigations 

 shall clear up more or loss of the obscurity at present surrounding 

 them. 



DEPREDATIONS IN MINNESOTA. 



There is one fact connected with the Oscinis problem in Minnesota 

 that seems to point especially to O. soror as the real depredator, and 

 not O. dirrsata^ and that is in the striking difference in the color of 

 the two, the former being black and the latter yellow, a difference 

 that could hardly have escaped the keen eyes of Doctor Lugger, and I 

 can not but feel that he was correct in his attributing the depredations 

 to the species now being considered. I strongly suspect that some of 

 the "deadheads" to which Doctor Fletcher has called attention in his 

 reports and other publications as occurring in the wheat fields of Mani- 

 toba and the Northwest Territories may have been to some extent due 

 to the work of this species also. 



Doctor Lugger seems not to have studied the several generations of 

 the species in his State (Minnesota), but gave his attention especially 

 to the one that proved the most destructive. From what has been 

 stated of the insect farther to the southward, it would appear that 

 there are the same number of broods as with O. carhonaria, the pest 

 wintering over in the young plants of fall wheat and grass. In Min- 

 nesota it evidently winters in the straw, from which it would seem 



