94 
Indiana University Studies 
Neuroterus (Dolichostrophus) dubius Bassett 
bisexual forms 
Figures 22, 53, 54 
FEMALE. — Head black; antennas brown, lighter basally, with 14 
segments, the third hardly half again as long as the fourth; thorax en- 
tirely black, about half again as long as wide and high, sparsely hairy 
on the edges, more hairy on the scutellum; mesonotum and scutellum 
largely smooth to distinctly roughened, in some varieties with more or 
less distinct and more or less continuous parapsidal grooves ; mesopleurae 
finely roughened; abdomen piceous black, not as shriveled as is usual in 
the genus, the segmentation visible, the hypopygium and ventral spine 
larger than usual in the subgenus; legs mostly yellow; cubitus clearly 
discontinuous; areolet small; length 1.2-1. 7 mm. (fig. 22). 
MALE. — Largely agrees with the female in color; eyes only mod- 
erately enlarged; the third segment of the antenna not longer than in 
the female, slightly curved, the radial area more or less closed. 
GALL. — A small, egg-shaped capsule; monothalamous, thin-walled, 
entirely hollow, 2.0-3. 0 mm. long by 1.0 mm. in diameter, pointed at one 
end, drying light yellowish brown, scatteringly set with short wool. On 
the edge of the leaf or on the aments of white oaks (figs. 53, 54). 
RANGE. — Massachusetts to California. Probably thruout North 
America, wherever white oaks occur. 
This very interesting insect is so distinct from other 
species of the subgenus as to suggest that it has had a very 
distinct evolution, but until we know more about the species, 
and know other closely related species, it will be well to keep 
dubius in Dolichostrophus. The symmetrically placed areolet, 
and in the male the elongate thorax, very small abdomen, 
and curved second antennal segment are clearly Dolicho- 
strophus characters. The roughened thorax, especially the 
roughened scutellum, the more or less clearly indicated par- 
apsidal grooves, the more rigid abdomen showing a clear 
segmentation, and the number of the antennal segments 
are characters which are unique to this species in the sub- 
genus. The number of antennal segments and the indication 
of parapsidal grooves are characters found in N. vesicula 
which belongs to a distinct subgenus, but it is not entirely 
evident that dubius can be a connecting form between 
Dolichostrophus and N eospathegaster , but rather that there 
has been some parallel evolution. Vesicula and dubius are 
the only American species of Neuroterus with 14 segments 
in the female and 15 in the male antennae. Altho several 
