110 Journal New York Entomological Society. [Vo]. xvii, 



the leaves in single file, most frequently with their heads directed 

 downwards. Isolated adults may often be seen with several pale yel- 

 lowish larvae in a row immediately behind their mothers. 



I have collected this species at Ft. Myer, Va., in the District of 

 Columbia and at Forest Hills, Mass. They were common where the 

 grass was growing rankly, but were not easy to find elsewhere. The 

 winged viviparee were always extremely rare. Wherever I have found 

 this species there seemed to be little need for the colonizing forms, 

 since even the wingless viviparse were not especially productive and 

 the aphids never occurred in such numbers as to seriously injure the 

 plants. The apical portion of many of the infested blades was yel- 

 lowed chiefly along the midrib as if caused by an earlier attack of the 

 insects when the leaves were more tender. This was especially notice- 

 able on many blades which carried a long row of adults and larvae 

 stationed below the yellowed part. But many infested leaves did not 

 appear to be injured at all. Thus the insects always had a luxuriant 

 growth of foliage before them and were never in danger of extermina- 

 tion by the death of the host as are many other species which multiply 

 so rapidly as to endanger their food supply. I observed this species 

 at several points around Washington on orchard grass during June, 

 July and August, 1907, all forms becoming very rare after June. 

 Other collections were made as follows: Washington, D. C, March 

 27, 1908, on tall red-top, Tricuspis scslerioides by Mr. C. N. Ainslie, 

 of the Bureau of Entomology ; wingless adults and well -advanced 

 larvae. Tennallytown, D. C, March 30, 1908, orchard grass; fairly 

 numerous, wingless adults, several pupae, larvae of all sizes. Forest 

 Hills, Mass., September, October to November 30, 1908, orchard grass. 

 Numerous until November. When last observed they were very rare 

 and were still reproducing. Same locality — April 8, 1909, orchard 

 grass, common ; wingless adults and larvae. 



Thorough search was made for the true sexes and eggs at Forest 

 Hills during November and December ; none were found on any part 

 of the plant or on the debris on the ground. This fact, together with 

 the early collections of reproducing adults when it would seem im- 

 possible for them to have developed from hibernating eggs, led me to 

 suspect that Hyalopients dactylidis winters over as viviparse. The true 

 sexes may not exist in this species. It is possible that some other 

 species may hibernate in the viviparous form even in Massachusetts on 

 hardy grasses like orchard grass and quack. I have often observed 



