GENERIC CLASSIFICATION OF APHIDIDAE. . 69 



Key to the Genera of the Pemphigini. 



1. Unguis of segment VI of alate form distinctly long and Aphis-like. .Mordwilkoja. 

 Unguis short and knob-like 2. 



2. Media once branched 3. 



Media simple 4. 



3. Antennae of alate form usually without secondary sensoria. Wings flat 



in repose Phloeomyzus . 



Antennas of alate form Avith secondary sensoria. Wings not flat in repose 



Pachypappella. 



4. Both media and cubitus present in hind wing 5. 



One oblique vein only in hind wing Dryopeia. 



5. Antennae of alate form without secondary sensoria. Wings flat in repose 



Rhizoctonus . 



Antennae of alate form with secondary sensoria. Wings not flat in repose. . . 6. 



6. Antennae of alate form rather short and thick. Stem mother with four-seg- 



mented antennae Pemphigus. 



Antennae of alate form rather long and slender. Stem mother with five-seg- 

 mented antennae Cornaphis. 



Genus CORNAPHIS Gillette. 

 Plate X, N-T. 

 1913. Cornaphis Gillette, Ann. Ent. Goc. Am., v. 6, p. 491. 



The genus Cornaphis was erected by Gillette for his species Coma- 

 phis populi. In his description it is stated that the genus is closely 

 related to Asiphum. In Cornaphis, however, there are large corni- 

 cles in the alate form and in other respects it seems that the genus is 

 closely related -to Pachypappella. In that genus, however, the 

 media is once forked, whereas in Cornaphis it appears to be simple, at 

 least as a rule. This difference has led the writer to retain a genus 

 with lactea as type rather than to place that species and similar 

 ones in Cornaphis. 



Characters. — Cornicles present; stem mother with five-segmented antennae and 

 without wax plates. Alate form with six-segmented antennae armed with rather 

 narrow sensoria; permanent sensoria ciliate. Fore wings with the media simple, hind 

 wings with both media and cubitus present; wax plates present in the apterous form; 

 sexes small, apterous and beakless; the oviparous female developing only one egg. 



Forms living in galls, the stem mother and the following forms living in the same 

 gall. 



Type (mono typical) , Cornaphis populi Gill. 



Genus DRYOPEIA Kirkaldy. 



Plate X, TJ-Y. " 



1857. Endeis Koch, Die Pflanzenliiuse Aphiden, p. 312. 



1889. Eudcis Ashmead, Ent. Amer., v. 5, p. 189. 



1904. Dryopeia Kirkaldy, The Entomologist, v. 37, p. 279. 



1917. Watabura Matsumura, Synopsis of the Pemphigidae of Japan, p. 89. 



In 1857 Koch erected his genus Endeis with two species, Delia 

 Koch and rorea Koch. This name was replaced by Dryopeia in 1904 

 by Kirkaldy, and bella has been definitely placed as the type. 



