GENERIC CLASSIFICATION OF APHIDIDAE. 77 
be a synonym of Prociphilus. Should poschingeri, however, be 
proven to be a distinct species it is so similar in all regards that 
Holzneria must remain a synonym. 
In 1917 Matsumura erected the genus Nishiyana with N. aomori- 
ensis Mats, as type, placing it close to Prociphilus. From this genus 
he separated it because of the absence of wax plates in the thorax 
and the somewhat shorter antennas. It must be borne in mind, 
however, that the specimens he had were fall migrants. Fall mi- 
grants of several species of Prociphilus show very reduced wax plates, 
and in some these are absent altogether, although distinct in the 
spring migrants. It is believed that this genus is in reality Proci- 
philus. 
Characters. — Cornicles aosent, wax plates present, very large and well developed. 
Stem mother with fi ve-segmented antennae. Alate form with six-segmented antennae 
armed with narrow transverse sensoria; secondary sensoria fringed. Fore wings with 
the media simple, hind wings with both media and cubitus present. Sexes small, 
apterous, and beakless. Oviparous females developing only one egg. Forms living 
in pseudogalls, the stem mother and her offspring together. 
Type (fixed by Gerstaecker, 1859), Aphis bumeliae Schr. 
Genus. THECABIUS Koch. 
Plate XIII, O-TJ. 
1857. • Thecabius Koch, Die Pflanzenlause, p. 294. 
1886. Bucktonia Liechtenstein, Monogr. d. pucerons, p. 16. 
The genus Thecabius was erected by Koch in 1857 for his species 
populneus. This species proves to be a synonym of Pemphigus 
affinis Kalt. In 1886 Lichtenstein erected the genus Bucktonia 
with affinis Kalt. as type. Bucktonia, therefore, becomes a synonym. 
Characters. — Cornicles absent; wax plates present but not prominently developed 
as in Prociphilus. Stem mother with five-segmented antennae and rather narrow 
sensoria, secondary sensoria not fringed; fore wings with media simple, hind wings 
with both media and cubitus present. Sexual forms small, apterous, and beakless, 
oviparous female developing only one egg. 
Forms living in galls, the stem mother usually living in a gall by herself. 
Type (monotypical), Thecabius populneus Koch (= Pemphigus affinis Kalt.) 
This genus is closely related to Prociphilus and it is with some 
hesitation that the writer places it as distinct. Certain species, 
such as patchii Gillette, which are undoubtedly congeneric with 
affinis, do not show the typical life habit of the stem mother living 
in a gall alone. However, the character of the sensoria and the 
undeveloped nature of the wax glands may serve to distinguish the 
genus. 
Tribe FORDINL 
Members of the Fordini are specialized subterranean forms mostly 
living in the nests of ants. The aphids excrete honeydew, in return 
for which they are tended carefully by these insects. The apterous 
