GENERIC CLASSIFICATION OF APHIDIDAE. 79 
closely related. The other characters mentioned by Theobald are 
seen to be present in the type species. The tubercles he figures and 
describes are the same and the spines on the first and second antennal 
segments are evidently the thickened, pointed, chitinized articula- 
tions of the segments common in insects of this type. We believe, 
therefore, that Rectinasus should be carried as a synonym of Forda. 
Westwood's genus was erected on his oetae which appears to belong 
here as recently indicated by the writer. 
Characters. — Cornicles wanting; apterous forms with five-segmented antennae and 
eyes of three facets. Alate form with five-segmented antennse and medium-sized 
oval, or more or less irregularly shaped sensoria. Fore wings with media simple; 
hind wings with both media and cubitus present, arising slightly apart. Subterranean 
forms living usually in the nests of ants and tended by them. 
Type (monotypical), Forda formicaria Heyden. 
Genus GEOICA Hart. 
Plate XIV, A-K. 
1894. Geoica Hart, 18th Rept. State Ent. 111., p. 101. 
1860. Tychea Passerini, Gli Afidi, p. 30. 
1906. Tycheoides Schouteden, Mem. Soe. Ent. Belg., v. 12, p. 194. 
1906. Kaltenbachiella Schouteden, Mem. Soc. Ent. Belg., v. 12, p. 194. , 
1909. Trifidaphis Del Guercio, Rivista Patol. Vegetale, n. s., v. 3, p. 332. 
1912. Tullgrenia V. d. Goot, Tijdschr. voor Ent., v. 15, p. 96. 
1913. Trinacriclla Del Guercio, Redia, v. 9, p. 169. 
1916. Serrataphis V. d. Goot, Zur Kenntniss der Blattlause Java's, p. 263. 
In 1860 Passerini used the generic name Tychea of Koch and placed 
as the typical species pliaseoli Pass. In 1863 he used the name 
again, listing several species but not the species included by Koch. 
Therefore his interpretation of the genus can not be correct. In 1894 
Hart erected his genus Geoica with squamosa as type. In 1906 
Schouteden noticed Passerini 's mistake and suggested the name 
Tycheoides but made eragrostidis Pass, the type. In the same year 
he erected Kaltenbachiella with mentkae Schout. as type. In the 
year 1909 Del Guercio erected Trifidaphis with radicicola Essig as 
type. In 1912 Van der Goot noted Passerines mistake and proposed 
the name Tullgrenia for the Tychea of Passerini. In 1916 Van der 
Goot erected the genus Serrataphis with lucifuga Zehntner as t} r pe. 
In studying cotypes and other • specimens of squamosa certain 
generic characters are evident. The species is subterranean. It has 
five-segmented antennse in the apterous form and six-segmented ones 
in the alate. It is true, however, that the apterous form sometimes 
has only four segments in the antennae and the alate five. 
Indeed, in some alate forms there is a five-segmented antenna on one 
side and a six-segmented one on the other. One of these five- 
segmented antennae was figured by Hart. One wing vein only was 
figured in the hind wing by Hart, but a very close examination shows 
that both the media and cubitus, though faint, are present. These 
are very difficult to trace in balsam mounts. In giving his name 
