SMULYAN: NEW ENGLAND TENTHREDELLA. 399 
The costa basal to the stigmal cell is of the same color, or gen- 
erally slightly paler than the corresponding portion in the front 
wing. The axillary vein is invariably, and the submedian and 
the anal veins are usually, as in the fore wings, in part or entirely 
paler than the other veins. 
In the descriptions only those features which are different from 
the corresponding features of the fore wings will be mentioned. 
Sexual Differences. 
Aside from the presence of the ovipositor in the female (PI. 4, 
fig. 2) and the presence of the more or less apparent claspers 
(PI. 4, fig. 4) in the male, the latter can at once be distinguished 
from the female by its comparative slenderness and consequent 
smaller size. Furthermore, the outline of the abdomen at its 
apex is distinctly different: in the male it is slightlj^ rounded off 
on each side, whereas in the female it is distinctly acute. Again, 
the posterior legs in the male are relatively strongly and stoutly 
formed and the hair on the posterior tibiae and tarsi is somewhat 
longer than the hair on the corresponding tibiae and tarsi of the 
female. The teeth of the claws in the male are not so widely 
spread, and often the difference in the length between the inner 
and the outer tooth does not seem to be so great as in the female 
of the same species. The head of the male is, as a rule, narrower 
behind the eyes than through them, and in those species where 
this is also true of the females, the difference is accentuated, so 
that in general it may be said that the head of the male is rela- 
tively narrower behind the eyes. However, this condition does 
not seem to be a primary one, but is apparently dependent upon 
and correlated with the slenderness of the body, for the females of 
the slenderer species, and the slenderer females of the stouter 
species often show such a condition. Finally, the lighter coloring 
or markings are, as a rule, more extensive in the males. 
Constancy of Characters and Definition of Color Terms. 
The writer has been unable to find in the material thus far 
examined, except in two or three instances, external anatomical 
characters which may be regarded as of primary taxonomic 
value. E?£cept in these instances, owing to their apparent varia- 
bility these characters are not absolutely reliable. The anatom- 
