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Indiana University Studies 
face almost naked of hairs; antennae brown, lighter basally, with 14 
segments, the third not much longer than the fourth; thorax large, 
robust, almost as wide as high, longer than wide, entirely black; mesono- 
tum wholly or in large part shagreened, usually with shallow but dis- 
tinct traces of parapsidal grooves and less distinct traces of anterior 
parallel and lateral lines, naked of hairs; scutellum of moderate width 
but somewhat elongate, naked of hairs; mesopleurse wholly, distinctly 
roughened ; abdomen a little larger than the thorax, rounded, only 
slightly angulate, slightly produced dorsally, the ventral spine short 
but distinct; tarsal claws only moderately fine, simple; wings not wholly 
clear but not definitely clouded, short ciliate on the hind margins, hardly 
ciliate elsewhere; areolet large to small, extending mostly to one side of 
the apex along the cubitus; radial cell only moderately narrow with the 
terminal portion of the subcosta quite short; the first abscissa angulate 
at a rather sharp angle, with a slight but distinct projection; length 
1. 5-3.0 mm. (figs. 9, 11, 15, 21). 
MALE. — Largely agrees in color with the female; eyes considerably 
enlarged, distinctly protruding beyond the cheeks; antenna with 15 seg- 
ments, the third distinctly curved, one half again as long as the fourth; 
parapsidal grooves less evident; areolet larger than in the female; radial 
area finely closed (figs. 10, 16). 
GALL. — A small, thin-shelled, globular bud or bark gall. Mono- 
thalamous, up to 3.0 mm. in diameter (bark galls smaller) ; rather thin- 
walled, quite globular, the bud galls succulent and shrivelling on drying, 
the bark galls more solid; almost smooth, but microscopically pebbled; 
bud galls colored light green and drying light or dark brown, bark galls 
colored with light buff yellow and brownish red in splotches; internally 
entirely hollow, without a distinct larval cell. In a terminal or lateral 
bud, partly covered by normal bud scales, or inserted in the slightly 
ruptured bark of stems; on white oaks and chestnut oaks (figs. 47, 48). 
RANGE. — Massachusetts to Michigan and Texas. Probably thruout 
the eastern half of North America wherever white oaks occur. 
This interesting insect is the only known American species 
which shows close relationship to the Old World group 
Spathegaster. An examination of the comparative descrip- 
tions of the two groups will make their relationships apparent, 
while emphasizing their distinctions. In such clear-cut char- 
acters as the number of antennal segments, the length of the 
third antennal segment, the toothing of the tarsal claws, the 
ciliation of the wings, and the closure of the radial cell, 
the two are entirely different. It is apparent that they have 
had a common origin in the remote past, and yet have been 
segregated long enough on distinct continents to allow evolu- 
tion along diverse lines. The most nearly related American 
species is Neuroterns (Dolichostrophus) irregularis, this re- 
