GEjSTEEIC classification of aphididae. 49 



Genus MICROSIPHUM Cholodkovsky. 

 1008. ilierosiphum Cholodkovsky, Zool. Aiiz., v. 32, p. 6S7. 

 Characters. — Head without prominent antennal tubercles, although with apparent 

 ones. Antennae of six segments, rather long and slender. Fore wings with the media 

 twice branched; hind wings with both media and cubitus present. Cornicles very- 

 short, not much longer than wide and often scarcely visible in the alate form. Cauda 

 extremely short and subcorneal or slightly rounded; anal plate rounded. 



Type (monotypical), Microsiphum ptannicae Choi. 



Genus PERGANDEIDIA Schouteden. 



Plate VI, KK-MM. 



1903. Pergan&ciiia Schouteden, Zool. Anz., v. 26, p. 685. 



1913. Longicaudus Van der Goot, Tijd. voor Ent., v. 56, p. 146. 



1915. Rhizoberlesia Del Guereio, Redia/v. 10, p. 246. 



1918. Yezosiphum Matsumura, Trans. Sapporo Nat. Hist. Soc, v. 7, pt. 1, p. 7. 



1918. Brackyunguis Das, Mem. Ind. Mus., v. 6, p. 227. 



The genus Pergandeidia was erected by Schouteden with his 

 ononidis as type. The characterization of the genus in this paper is 

 based on specimens of the species received from Schouteden, and 

 though it does not agree with the characterization of the genus as 

 sometimes given, it seems necessary to follow the type species in 

 forming a conception of the genus. In 1913 Van der Goot erected 

 the genus Longicaudus and placed trirhodus Walker as type. In 

 studying this species differences sufficient for good generic distinc- 

 tion have not been found, and, therefore, the conclusion may be 

 drawn that Longicaudus is a synonym of Pergandeidia. Del Guereio 's 

 genus is placed here also, although a study of the type species, which 

 is not available, possibly may show the cauda to be somewhat different. 



Characters. — Head with no prominent antennal tubercles; antennae of six segments. 

 Fore wings with media twice branched, hind wings with both media and cubitus 

 present. Cornicles very short, almost as wide as long. Cauda very long and broad. 



Type (monotypical), Pergandeidia, ononidis Schout. 



Genus RHOPALOSIPHUM Koch. 



Plate VI, FF-JJ. 



1854. EttopalosipJium Koch, Die Pflanz. Aphiden, p. 23. 



1860. Sipliocoryne Passerini, Gh Afidi, p. 28. 



1882. Bhopalosiphon Scudder, Nomenclator Zoologieus. 



1910. Coloradoa Wilson, Ann. Ent. Soe. Am., v. 3, p. 323. 



1915. Siplionaphis Van der Goot, Beitrage zur Kennt. d. Holl. Blattlause, p. 238. 



1918. Stephensonia Das, Mem. Ind. Mus., v. 6, p. 175. 



1856. (Type fixation) Gerstaecker, Bericht for 1854, p. 162. 



There has been much confusion in regard to this genus. Koch 

 included a number of diverse species. In 1856 Gerstaecker defi- 

 nitely set Aphis nympheae L. as type. Overlooking this, Passerini 

 in 1860 set persicae Sulz. as type. In 1863, however, he changed this 

 name to dianthi Schrank. In 1860 Passerini erected the genus Sipho- 

 coryne with A. nympheae L. as type. Having the same type this 

 must, therefore, become a synonym of Rhopalosiphum. In 1S63 

 Passerini placed nympheae in Rhopalosiphum, although he set dianthi 

 141613°— 20— Bull. 826 i 



