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Indiana University Studies 
KEY TO DESCRIBED CYNIPS 
DIAGNOSTIC CHARACTERS OF AGAMIC FORMS. Usually 
rather large and robust insects with the mesonotum punctate and more 
or less hairy, usually with complete parapsidal grooves, an undivided 
or finely divided foveal groove, a hypopygial spine which is large and 
distinctly broadened nearer the tip (except in short- winged Acraspis) 
and which terminates in a prominent tuft of long hairs; tarsal claws 
which are strongly or at least weakly toothed (except in mellea ) ; wings 
long or much reduced, the long wings 1.17 to 1.60 times the body 
length, the short wings of various lengths down to 0.14 times the body 
length; the long wings usually with a smoky patch at the base of the 
cubital cell, sometimes with additional spots or smoky patches in this 
and other cells. Living (with a few exceptions) in monothalamous, 
highly separable leaf galls which are usually spherical, with the cen- 
trally placed larval cell closely embedded in dense, radiating fibers or 
more solid, spongy or crystalline material, the galls in some cases 
of more diverse form, especially in the subgenus Antron. Strictly con- 
fined to white oaks. Galls appearing in early summer, the adults 
maturing early in the fall, but delaying emergence until cold weather, 
from early winter to early spring of the first year (and successive years 
in C. fulvicollis ) . 
DIAGNOSTIC CHARACTERS OF BISEXUAL FORMS. More 
slender insects, with the mesonotum largely smooth and naked, the 
hypopygial spine as in the agamic form but more slender; tarsal claws 
toothed; wings always long, 1.17 to 1.60 times the body length, less 
heavily spotted than in agamic forms; the males with one more anten- 
nal segment than in the female, with the third segment slightly curved, 
and with the abdomen long-petiolate. Galls always small, seed-like or 
bladdery, thin-walled cells in the undeveloped buds of the white oaks. 
Galls appearing with the opening buds in the spring, the adults matur- 
ing within a very few weeks. 
1. Wings always 1.50 times the body length, cells always clear (ex- 
cept for a trace of a blotch at base of cubitus); hypopygial spine 
rather broad, rather drawn out ventrally. Entirely Old World 
species. Subgenus Cynips, 4 
Wings from 0.14 to 1.60 times the body length, wing cells clear 
or spotted, spines various. Entirely American species. 2 
2. Hypopygial spine rather broad, but drawn out ventrally (see figs. 
175-190); wings normally 1.60 times the body length, or much re- 
duced in length; with a heavy patch and sometimes spots in cubi- 
tal cell. Pacific Coast species not known east of the Sierras except 
in southern Arizona. Subgenus Antron, 7 
