59 



widely spread. It "was seen at Ames in small numbers on oats, but in 

 this case also accompanied by parasites ; and wbile it is probable that 

 wheat and oats may be affected by the louse another year, I think we 

 may depend npon the parasites being sufficiently numerous to prevent 

 serious loss. It would, therefore, not seem advisable to reduce in any 

 degree the planting of wheat or oats or any of the crops that may be 

 affected by this species on account of possible loss from this pest. 



The Dogwood Plant-louse, which has been referred to in previous re- 

 ports, has been observed further and some additional facts secured, but 

 there are still some points of importance to be determined. Eggs of 

 this species and of the Dogwood Aphis (Aphis eornicola) were deposited 

 freely on some small dogwood bushes near my office last fall, and I 

 had an opportunity of watching them pretty closely during the spring. 

 The eggs near the ground seemed to pass the winter most perfectly, 

 and for the Schizoneura hatched in fair numbers in spring, a short time 

 before the blossoming of the Dogwood. The insects gathered upon the 

 expanding leaves and also on the blossom buds, and as the latter 

 opened they seemed to gather by preference in the bunches of blossoms 

 clustering upon the stems and at the bases of individual blossoms. 

 Apparently the second or third generation acquired wings, and the 

 Schizoneura then disappeared entirely from the Dogwood. They were 

 not to be found on grasses for some time later, but they would neces- 

 sarily be scattered widely and difficult to find at first. 



During the autumn I received word from a Mr. Bower, of Norway, 

 that his corn had been troubled with plant-lice, and he sent me sam- 

 ples of Setaria infested with Schizoneura, which he said were the same 

 as he had been troubled with on his corn. 



Thinking it probable that it was Aphis maidis that was affecting the 

 corn, and not the Schizoneura, I requested him to send samples if he 

 could then find them of the lice on the corn roots, and he soon sent me 

 some roots of corn on which were a number of Schizoneurae resembling 

 in every respect the Schizoneura so common on grass. Some of these 

 were quite evidently acquiring wings, and shortly after I secured from 

 them a winged individual, which agrees closely with Schizoneura corni, 

 except that the antenna! sensory pits are not so distinctly developed. 



As the specimen was mounted while still quite fresh, there is a possi- 

 bility that the sensory pits had not become as well marked by the rigid 

 chitinous border as in more mature individuals, and while I can not 

 affirm their identity it seems probable that they are the same. If iden- 

 tical with the species affecting the Foxtail, it is evident that there is 

 an important relation between this weed and the corn with which it 

 grows so abundantly. It is certain that we have in the species of 

 Schizoneura here noticed another corn pest that is easily equal to the 

 common corn-root louse in its power to injure this important crop. 



The Clover-seed Midge has become a serious pest in many parts of 

 the State, and, while it has been observed before and attention called to 



