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-TT. 



1857. Thecabius Kcch, Die Pfianzcnlause, 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 patcliii 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 FORDINI. 



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 



