GENERIC CLASSIFICATION OF APHIDIDAE, 43 



Characters. — Head without prominent antennal tubercles. Antennae of six seg- 

 ments and armed with subcircular sensoria. Fore wings with the media twice 

 branched, hind wings with both media and cubitus present. Cornicles cylindrical, 

 often short, though sometimes moderately long; Cauda short, broad, and abruptly 

 conical, never elongate and constricted as in Aphis. Males usually winged. Ovi- 

 parous forms apterous. 



Type (fixed by Del Guercio, 1907), Aphis pyri Koch. 



Genus APHIS L. 

 Plate VI, G-I. 



1758. Aphis Linnaeus, Systema Naturae, 10th ed., p. 451. 



1817. Loxerates Rafinesque, Am. Mo. Mag. & Crit. Review, v. 1, p. 361. 



1907. Uraphis Del Guercio, Redia, v. 4, p. 192. 



1907. Mkrosiphon Del Guercio, Redia, v. 4, p. 192. 



1913. Myzaphis Van der Goot, Tijd. voor Ent., v. 56, p. 96. 



1913. SlenapMs Del Guercio, Redia, v. 9, p. 185. 



1916. Longiunguis Van der Goot, Zur Kenntniss der Blattlause Java's, p. 112. 



1916. MelanapMs Van der Goot, Zur Kenntniss der Blattlause Java's, p. 61. 



1917. Abnra Matsumura, Jour. Coll. Agr. Tohoku Univ., v. 7, pt. 6, p. 407. 

 1917. Arimakia Matsumura, Jour. Coll. Agr. Tohoku Univ., v. 7, pt. 6, p. 405. 



A number of species were included in the original genus by Lin- 

 naeus. Of these Lamarck set Aphis ulmi L. as type in 1801, and in 

 1802 Latreille set Aphis sambuci L. as type. Aphis ulmi L. 

 is, according to Passerini, Eriosoma lanuginosa Hartig and the spe- 

 cies now placed in Tetraneura. Sambuci is retained here as type 

 and a request will be submitted that this species be fixed definitely 

 by the International Commission. It would greatly disarrange the 

 economic literature to change the meaning of this common name. 



In 1907 Del Guercio erected two genera, Uraphis and Microsiphon 

 based on the relative length of the cornicles and cauda. When con- 

 sidering certain individual species this would appear as a very fair 

 character for use. But when large series of species are studied it will 

 be found that in the species having the cauda of the typical Aphis 

 shape there are all gradations of cornicles from the very short to 

 the very long. This will be seen also in the forms having the abruptly 

 conical cauda. Some species have very short cornicles and some 

 quite long ones. Moreover, in the same species the cornicles in the 

 different forms will bear a different relation to the length of the 

 cauda. Species, therefore, having cornicles and cauda of essentially 

 the same character should not be used as types of different genera 

 depending on the length of the cornicles. If this were the case, 

 certain species which are close to the border line of separation would 

 on some individuals fall in one genus and on other individuals fall in a 

 different genus. Under this rule, sacchari Zehnt. would, it is believed, 

 belong to the genus Aphis, and Longiunguis, therefore, be a synonym 

 of Aphis. Likewise the genus Melanaphis would be a synonym of 

 Aphis. This genus was erected with bambusae Kirk, as type. The 

 cornicles are short but the cauda is aphis-like. Where the generic 

 characters are considered, the genus appears a synonym. 



