448 ANNUAL REPORT OF NEW-YORK 



HICKORT. LEAVES. 



belonging to the oak, which is perfectly congeneric with it. None 

 of the figures in Koch's works correspond w^ith these insects, and 

 the genus to which they pertain is evidently unknown to him. 

 But on gathering from different sources the details of the Euro- 

 pean plant-louse named Quercus, on which the genus Phylloxera 

 has been founded by Fonscolomb, we find such a full coincidence 

 as to assure us that our insects are congeneric with that species. 

 We cannot but deem that the observation of M. Amy ot (Ann. Soc. 

 Ent. 2d series, v. p. 485), that in that species the three oblique 

 veins arise directly from the outer margin of the wings, is inexact, 

 as such a structure would be a perfect anomaly among the species 

 of this family. Should that character, however, be as stated by 

 M. Amyot, our insects would constitute a new genus, since in 

 them the usual longitudinal rib-vein from which the oblique veins 

 are given off is perfectly distinct. 



2. Puncturing the leaves and sucking their juices. 



167. Hickory gat -louse, Callipterus Caryellus, Fitch. (Homoptera, 



AphidsB.) 



Scattered upon the under sides of the leaves, a small pale yel- 

 low plant-louse with white antennae alternated with black rings, 

 and pellucid wings laid flat upon its back, its abdomen egg- 

 shaped, somewhat flattened and with only minute rudimentary 

 honey tubes. Length 0.12. See Transactions, 1854, p. 869. 



This and the four following species of very small delicate 

 bright-colored plant-lice inhabiting hickory leaves were described 

 in my First Report, at which time I remarked that they with 

 other similar insects occurring on oaks and other trees formed a 

 group so very distinct from the common species of the genus 

 Aphis that they would probably be regarded as entitled to the 

 rank of an independent genus. The same year in which that 

 Report was published the portion of M. Koch's beautifully illus- 

 trated work (Die Pflanzenlause Aphiden) in which a few European 

 species similar to these is given, made its appearance. These 

 insects are therein formed into a new genus, to w^hich the name 

 Callipterus, 1. e. beautiful winged, is given. And the European 

 C. Juglandicola of Koch appears closely related to this present 

 species, though suflSiciently distinguished from it by the black 



