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festing the roots of grasses during the summer with oue occurring on 

 the leaves of dogwood during autumn. The full import of this connec- 

 tion from the economic stand-point can not be known till it is determined 

 how many species of grasses are affected by the root form and to what 

 extent the migration to dogwood exposes it to attack. If its occurrence 

 is confined to the annual grasses (and it seems to occur only .011 these), 

 its importance to the farmer will be much less than if it is found to work 

 also on perennial species. 



A brief statement of the connection between these two forms was 

 published in Insect Life (Vol. II, pp. 108-9), but a fuller account,.with 

 details of observations, is proper at this time. 



My attention was first called to this species on September 15, when I 

 noticed the air was filled with small insects, which on capture were 

 found to be plant-lice of the genus Schizoneura. Their immense num- 

 bers, filling the air as far as could be seen in all directions, naturally 

 excited my interest, and I walked some distance in the direction from 

 which they seemed mainly to come (which was with the wind), but 

 without locating their origin, except to observe that they were resting 

 on all sorts of plants and were very plentiful along roads and paths 

 where fox-tail and other grasses were plenty. Upon examination I de- 

 termined the specimens gathered to be Schizoneura corni Fab., speci- 

 mens of which I had gathered a year or two ago from dogwood. It 

 seemed difficult, however, to account for such an immense swarm of them 

 when dogwood is not especially abundant in the immediate vicinity and 

 had not been observed as infested with aphidSc In looking over de- 

 scriptions of allied species I was struck by the close agreement with 

 descriptions of Schizoneura panicola Thos., and, following this lead, I 

 examined the roots of Setaria and Panicum on September 16, when the 

 winged forms were again numerous in the air. My search was almost 

 immediately rewarded with the finding of numerous wingless Schizo- 

 neurce, and among them some which showed wing-pads and two with wings 

 partly expanded. These were compared carefully with winged corni 

 found flying and also with corni from dogwood, and showed such close 

 agreement that I felt it important to follow the matter up. One of the 

 specimens, with wings partly developed, was mounted in balsam for 

 future reference; the others, on grass roots, were put in breeding jars. 

 Their subsequent history will be stated later on. 



Examinations in the field on the 18th showed lice still somewhat 

 plenty on grass roots, though the Setaria examined failed to show them 

 in very great abundance. Examinations the same day, of the dogwood 

 in the timber near, showed on the very first bush noticed numbers of 

 the winged (pseudogyne) individuals, and with them numbers of small 

 larvae evidently just extruded. The colonies accompanying each 

 pscudogyne contained from one to a number of larvae, but none of these 

 could have been more than a day or two old, all very small, scarcely 

 larger than when first born. In no case could I find a leaf on any of 

 23479— No. 22 3 





