GALL APHIDS OF THE ELM. 197 



Wings hyaline ; costa to the base of the stigma very pale fuscous, the 

 stigma a little darker; veins fuscous, the 3rd discoidal hyaline half- 

 way from its base to the fork; hind wings with the veins subhyaline. 

 Length to tip of wings .05 — .07 inch. 



"Nine specimens. The antennae do not quite attain the origin of the 

 first discoidal when the wings are expanded, and the stigma is twice as 

 long as wide and hunched both anteriorly and posteriorly, its tips mod- 

 erately acute. Occurs in elm-leaf galls, which are well described by 

 Fitch (loc. cit.)." 



Riley in the Riley-Monell paper gives the following discus- 

 sion of Colopha uhnicola which is reproduced entire : 



"COLOPHA* ULMICOLA (Fitch). 



"(Forming cock's-comb-like galls (Fig. 129 a) on the upper surface of 

 the leaves of Ulmus amcricana, the galls appearing with the opening 

 of the leaves, and turning brown and black in late summer.) 



"Another very common gall, which may be called the Cock's-comb Elm 

 Gall {ulmi-ulmicola) is also fovmd on the White Elm, and particularly 

 as in the case of the previous gall, on young trees. It was well described 

 by Fitchf as an excrescence or follicle like a cock's comb, arising 

 abruptly on the tipper side of the leaves, usually one inch long and V* of 

 an inch high, compressed and its sides wrinkled perpendicularly and its 

 summit irregularly gashed and toothed ; of a paler green color than the 



"*The bibliography of this species very well illustrates the confusion 

 that too often surrounds the proper determination, not only of insects 

 of this family, but of all orders. It is due to three causes, not easily re- 

 moved : 1st, the miserably insufficient nature of the earlier descriptions 

 and definitions ; 2nd, the isolation of the earlier English entomologists 

 from those of the continent, and the dual nomenclature that has arisen 

 from independent work; 3rd, the want of a common ground for generic 

 characterization. Walsh referred the species to TJiclaxes, which has, 

 however, S-jointed antennae. Vacuna, Heyden, is synonymous with 

 Thchixes, though Walker would restrict the former to alni, Schrank, 

 and the latter to dryo[>]iUa, Schrank ("The Zoologist", London, February 

 1870, p. 2001), without pointing out generic differences, as the want of 

 a fork in the cubital vein in Koch's figure is clearly an error of the 

 artist. Mr. Monell founded the genus Colopha for tdinicola on the fact 

 that the antennae of the winged female are 6-jointed. Such a diffeience 

 can hardly have generic value when we find uhnicola occasionally with 

 but 5 antcnnal joints, and (if Huxley is correct in his determination) 

 dryophila sometimes with six (Trans. Linn. Soc. xxii, pp. 203, 234), 

 But. taken in connection with the fact that uhnicola is a flocculent 

 species, the true female producing but one large egg, while dryof^liila is 

 without flocculcnce, the female (according to Huxley) laying many eggs, 

 Colopha, considering uhnicola as a type, may be accepted as a good 

 genus." 



fFitch Report on the Noxious Insects of N. Y. 347. 



