Kinsey: The Genus Neuroterus 
117 
The five varieties known for this insect occur on four 
different hosts, in five distinct faunal areas. I have seen 
galls representing probably an undescribed variety from 
Quercus prinoides in Oklahoma. A total of about 40 varieties 
may occur in the United States. 
Wells (1921) has independently arrived at the conclusion 
that the gall of this insect is evolutionarily primitive, con- 
firming my opinion for all of the stem-gall species of this 
genus. 
No complete life history is known in this species, but we 
have what would appear to be supplementary parts of the 
story from the several varieties. Varieties rileyi and thomp- 
soni have the insects and galls differing mainly in color, size, 
host, and distribution, and in the more significant matters of 
sexual nature and seasonal occurrence. Rileyi, with the larger 
galls and the larger females, is not known from the males, 
has galls which begin development in late summer, and insects 
which emerge in April or early May. This is an exact descrip- 
tion of any agamic generation of the other Dolichostrophus 
species which have known life histories; while thompsoni, 
with smaller females, with males, and with smaller galls, 
starts development in May and emerges in early summer, 
exactly fitting conditions for a bisexual generation in the 
subgenus. It would appear that the alternate generations of 
all these varieties may be predicted, with considerable cer- 
tainty, to have very similar galls and insects, the galls of 
the bisexual generations being smaller and occurring on the 
younger twigs, the insects differing very little except in having 
the agamic female larger. The differences between the de- 
scribed varieties may be accredited in part to the different 
hosts and distributions, but undoubtedly part of it is an 
expression of the differences between agamic and bisexual 
forms. These biologic data have been known for some years, 
but their connection was not apparent until the varietal rela- 
tions of rileyi and thompsoni were seen, — which is an illustra- 
tion of the value of the variety concept! 
This insect is not very closely related to any other species 
in Dolichostrophus. The very elongate thorax^ the distinctly 
petiolate female abdomen, and the origin of the cubitus below 
the midpoint of the basalis, are characters not found else- 
where in the subgenus, but another subgenus should not now 
be named for rileyi. 
