GENEEIC 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, nei'er 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. Microsiphon Del Guercio, Redia, v. 4, p. 192. 
1913. Myzaphis Van der Goot, Tijd. voor Ent., v. 56, p. .96. 
1913. Stenaphis Del Guercio, Redia, v. 9, p. 1S5. 
1916. Longiunguis Van der Goot, Zur Kenntniss der Blattlause Java's, p. 112. 
1916. Melanaphis Van der Goot, Zur Kenntniss der Blattlause Java's, p. 61. 
1917. Abisra Matsumura, Jour. Coll. Agr. Tohoku Univ., v. 7, pt. 6, p. 407. 
1917. Animated 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 samhuci L. as type. Aphis ulmi L. 
is, according to Passerini, Eriosoma lanuginosa Hartig and the spe- 
cies now placed in Tetraneura. Sambvxi 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. Lender 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 vambusae Kirk, as type. The 
cornicles are short but the cauda is aphis-like. Where the generic 
characters are considered, the genus appears a synonym. 
