December, '10] DAVIS: ILLINOIS aphidid.e 489 



the three last abdominal segments. The cornicles are only two to 

 two and a half times the length of the tarsi. The style is pale or 

 pale greenish and not dusky or black as given in the original descrip- 

 tion. 



*A. populifolice Fitch: Cat. Homopt. N. Y. 1851, p. 66. This very 

 interesting species was found infesting the tender terminal shoots 

 and under surfaces of the leaves of the quaking aspen {Populus tremu- 

 loides), June 27, 1910, in one of the Chicago parks. All of the P. 

 tremuloides in this park had recently been secured from their native 

 habitat in Indiana, just across the state hne and not far from Chicago. 

 The same species was also taken on the common Carolina poplar 

 (P. delioides) in a Chicago nursery, June 30, 1910. August 23, the 

 trees so heavily infested nearly two months before were visited, but 

 not a single aphis could be found. Through the kindness of Mr. 

 J. T, Monell I have had the privilege of examining specimens in his 

 collections of this same species and which he has long considered to 

 be the populifolice of Fitch. These Monell specimens are labeled 

 ''293a; Washington, D. C, Sept. 30, 1880, Populus alba. From Theo. 

 Pergande." 



From the brief description given by Fitch it is difficult if not impos- 

 sible to identify the species with certainty, although one might be 

 led to believe that he was dealing with a species of the genus Melanox- 

 antherum. Notwithstanding the slight differences in measurements 

 the aphid in question is possibly the one Fitch was dealing with. 

 Populifolice Fitch has generally been considered a species of the genus 

 Chaitophorus but the one here considered, although showing marked 

 Chaitophorus tendencies, is nearest related to the genus Aphis. 



The Chait. populifolice as described by Oestlund^ is clearly not 

 Fitch's species. Through the courtesy of Professor Oestlund, I have 

 examined the species which he described and questionably referred 

 to the populifolice Fitch. It is a typical Chaitophorus and a new species 

 which I propose shall hereafter be known as Chaitophorus populi- 

 folice Oestlund. These two species and a new species on poplar are 

 fully described and discussed in another paper soon to be published 

 and it is therefore sufficient to give here simply a brief description 

 of the species which is being considered bj' the writer as Fitch's 

 populifolice. 



Wingless viviparous female. — Entire body dark reddish brown with very con- 

 spicuous white flocculent patches, namely a row on each side of the abdomen and 

 two more or less regular longitudinal rows on the dorsum, one on each side of the 

 median line. Under surface of abdomen with a large patch of whitish pulverulence. 

 Antennae not reaching to the base of cornicles; segment III longest, it being about 

 twice the length of IV, IV and V subequal, base VI about half the length of V and 

 a third the length of the filament. Legs with femur black excepting extreme base, 

 tibia whitish except distal ends which are black and the tarsus black. Style black 

 and moderately long, nearly one half the length of cornicles. Cornicles black, 

 rather long, and cylindrical. 



1 BuU. Geol. and Nat. Hist. Surv. Minn., No. 4 (1887), p. 38. 



