40 



reared from grass roots and allowed to colonize on Cornus leaf there are 

 the full number common to corni and show distinctly. Mr. Oestiuud's 

 statement that they are indistinct and but three or four in number 

 might, I think, apply to an extreme variation or to specimens fresh from 

 the ground. The dark spot on the dorsum of the abdomen is not only 

 variable in size but differs much in appearance with the age of the speci- 

 men and in dead or preserved specimens. While I am free to admit 

 some puzzling questions, I am strongly convinced of the main point here 

 claimed. There is^ certainly much more of interest to be learned re- 

 garding the species. I feel that only a beginning has been made, and 

 shall watch eagerly for further developments. As the Aphides are so 

 uncertain in their appearances and can not be depended upon to fur- 

 nish material in abundance in every locality, it will add to the certainty 

 of completing the history of this species if entomologists in various 

 localities will make such observations as possible the coming season. 



If my conclusions are correct the synonomy for this species will read 

 as follows : 



(1794) ApHs corni Fabricius, Ent. Syst., IV, 214. 



(1860) Scliizoneura venusta Passerini, Gli Afidi, p. 38. 



(1862) Eriosomat fungicola Walhh, Proc. Ent. Soc. Pbila., I, 304. 



(1862) Eriosoma? cornicola Walsh, Proc. Ent. Soc. Pbila., I, 304. 



(1879) Scliizoneura panicola Tbos., 8tb Rep. 111. Ent., p. 138. 



SUMMARY. 



SchizoneuraB abundant on grass roots and assuming winged form in 

 latter part of September (15-28) and on several days during this time the 

 air was filled with like insects, and immediately following these flights 

 apparently identical Aphides were colonizing on leaves of dogwood, 

 which had hitherto been free from them. 



Scliizoneura (winged pseudogyne) reared from grass roots and trans- 

 ferred to leaves of Cornus established colonies apparently identical with 

 those occurring normally on Cornus. 



Scliizoneura (apterous individuals) in some number remain on grass 

 roots and are associated with apterous males and females, the females 

 of which are oviparous. 



Individuals of these different forms agree with each other and with 

 descriptions of both corni and panicola and differences do not exceed 

 the range of variation common to species of Aphididoe. 



CONCLUSION. 



Taking all these facts into consideration, I believe that the species of 

 Scliizoneura infesting grass roots and dogwood leaves and described as 

 distinct species are identical. 



That the winged generation of asexual individuals produced from 

 grass roots in autumn migrate to leaves of dogwood of different species 

 and establish colonies of apterous individuals, which become sexually 

 mature and the females of which deposit eggs on dogw T ood. 



