GENERIC CLASSIFICATION- OF APHIDIDAE. 81 



Characters. — -Cornicles wanting; apterous form usually •with five-segmented antennae 

 and eyes of three facets. With the intermediate forms more facets may occur. Alate 

 form with usually six-segmented antennae and rather large oval sensoria with distinct 

 rims. Fore wings with media simple. Hind wings with both media and cubitus 

 present, though these may be faint and almost obscured in balsam. Cauda large 

 and somewhat rectangular or rounded. Subterranean forms living on the roots of 

 plants. Sexes small, apterous, and beakless. 



Type (monotypical), Geoica squamosa Halt. 



Genus PARACLETUS Heyden. 

 . Plate XIV, L-S. 



1S37. Paraclctus Heyden, Mus. Sinkbg., v. 2, p. 295. 



The genus Paracletus is closely related to Forda Heyden from which 

 it may be distinguished by the number of antennal segments in both 

 alate and apterous forms. As with other genera of this tribe the eyes 

 of the apterous form consist of three facets. Intermediate forms 

 often occur, however, in which the intermediate nature is indicated 

 only by the eyes which have the beginnings of compound eyes, such 

 as are found in the alate form. There never are, however, complete 

 compound eyes. The genus was erected by Heyden in 1837. The 

 species live in close association with ants. 



Characters. — Cornicles absent. Apterous form with six-segmented antennae and 

 eyes of three facets; alate form with six-segmented antennae which possess many 

 rather small, oval sensoria. Fore wings with media simple, hind wings with both media 

 and cubitus present, arising some distance apart. Thorax with a central wax plate. 

 Forms living in the nest of ants and cared for by them. Sexes small, apterous, and 

 beakless. In some cases only one claw is met with on the foot, while in other cases 

 the normal number of two is present. This appears to be no definite character, as 

 sometimes a claw is dropped from one foot and sometimes from another. 



Type (monotypical), Paracletus cimiciformis Heyden. 



Subfamily IV, HORMAPHXDINAE. 



The genera placed in this subfamily have usually been placed 

 with the Eriosomatinae, or Pemphiginae, as it has been sometimes 

 called. Mordwilko, however, placed these forms as his third tribe 

 under the subfamily Aphidinae next to his tribe Callipterea, 

 Something can be said in favor of both of these placings. In 

 the first instance, the species in general form, antennal structure, 

 and habit of gall formation are no doubt suggestive of the 

 Eriosomatinae. On the other hand, their structure in regard to 

 cauda and anal plate is very like the Callipterina and the sexual 

 forms appear to have a development of their own, although they 

 are nearer in many ways to the Aphidinae than to the Eriosomatinae. 



It is the author's belief that these forms should constitute a sepa- 

 rate subfamily. It has developed the habit of gall formation 

 and the sensory characters which usually accompany it, while at 

 the same time it has retained in the sexual female the normal develop- 



141613°— 20— Bull. 826 6 



