No. 150.] 
353 
pallid brown, the tarsi black, the femurs paler at their bases. The 
several pairs of legs equal each other in length, being about 0.24 
long when extended, of which length the tarsus embraces one-half. 
The several joints of the tarsus are of the same relative length as in 
other species; the short basal joint however, is much more indis¬ 
tinct than usual, insomuch that a minute examination of several 
specimens is required ere one is met with showing this joint dis¬ 
tinctly.* This character, and also the neuration of the wings, clear¬ 
ly shows that this species belongs to the genus Cecidotnyia, and not 
to Macquart’s genus Lestremia , nor Meigen’s Lasioptera. 
In the male, the antenna; (fig. d,) are three-fourths of the length 
of the body, with the joints of a short oval and nearly globular form, 
the diameter hardly equalling the length: each joint is surrounded 
with a verticil of longish hairs. The terminal joint does not differ 
from the preceding ones. The two basal joints arc compacted toge¬ 
ther as in the female. The antennm diminish very slightly in dia¬ 
meter towards their tips. The filaments separating the joints are 
smoky-translucent, nearly as long as the joints, and about one-third 
of their diameter. The abdomen (fig. 2,) is cylindric or slightly 
tapering towards its tip, and consists of seven joints beside the ter¬ 
minal one, which (viewed from beneath, vide fig. c,) consists of a 
transversely oval joint, giving off two robust processes, armed with 
incurved hooks at their tips; and between these processes at their 
base are two exceedingly minute papillae. As ordinarily seen, in 
the living specimen, the abdomen is of a brownish-black color, more 
or less widely marked at the sutures with pallid fulvous or smoky 
w'hitish lines. In all other .points the male coincides with the 
female in its characters. 
Its duration. That the fly which comes out in the spring conti¬ 
nues but a very short time, I infer from the following data. A num¬ 
ber of wheat plants, containing pupae, were transplanted into a box 
of earth, April 21st, and inspected daily. On the morning of May 
1st, about half of them were found fo have sent out the perfect fly 
* How well the engraver lias executed his task will be obvious by passing a magni- 
tier over the plate; The joints of the tarsi in tig. 3, and other minute details, scarce* 
ly. if at all perceptible to the naked eye, will then be distinctly recognised. 
[Assembly, No. 150.] 25 
