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Indiana University Studies 
is separated by its slightly greater wing-body ratio, shorter 
radial cell due to the more strongly curved second abscissa 
of the radius, and its more elongate hypopygial spine. The 
uniform galls — all of them thin-shelled, spherical, hollow oak 
apples in which the larval cell is supported by relatively few, 
radiating fibers — testify to the unity of the group. The 
eastern species centricola is rather remote in insect characters 
from the three southwestern species. 
The subgenus is of much interest because four of the twelve 
varieties have wings that are of reduced length, the reduction 
however being only fifteen, thirty-five, and thirty-seven per 
cent of the length normal for the subgenus. 
The subgenus is of further note because the galls of all the 
varieties of the two species bella and dugesi are identical. 
We have not recognized the bisexual form of any variety of 
Atrusca. 
Cynips (Atrusca) dugesi (Mayr) 
agamic forms 
FEMALE. — The head rufous or darker, the antennae dark brown, 
more rufous basally; thorax not particularly large, bright or dark 
rufous, in some varieties darker to black in places; anterior parallel 
lines often evident, more often nearly obliterated; lateral lines not wide, 
quite evident; scutellum moderately rugose, smoother anteriorly, slightly 
raised on the mid-line, with two rather deep, more or less definite foveae; 
the hypopygial spine longer, more slender than in bella; wings long or 
short, from 1.35 to 0.85 of the body in length; the first abscissa of the 
radius without a projecting point; the second abscissa of the radius 
with or without an enlarged tip; with large, smoky patches about the 
base of the cubitus and at the base of the cubital cell; darker brown 
spots of irregular shape in the cubital cell, these spots often coalescing 
into a few irregular blotches; a much lighter, more indefinite cloud in 
the discoidal cell; the radial cell unspotted; length 2.0 to 3.2 mm. 
GALL. — Thin-shelled, spherical, sessile, dull brown, unspotted, aver- 
aging 16.0 mm. in diameter, with the larval cell held centrally by fine, 
radiating fibers. Apparently not to be distinguished from galls of 
Cynips bella (q.v.). On the leaves of practically all of the white oaks 
of the regions in which the several varieties occur. Figure 197. 
RANGE. — Southern Colorado and West Texas to Central Mexico; 
probably further south as far as white oaks extend. Figure 44. 
This species, together with Cynips bella , produces the com- 
mon oak apple gall of our Southwest. The galls of all the va- 
