42 
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, 
clearly shows that this species belongs to the genus Cecidomyia, 
and not to Macquart’s genus Lestrimia, nor Meigen’s Lasioptera. 
In the male, the antenne (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 sur- 
rounded with a verticil of longish hairs. The terminal joint does 
not differ from the preceding ones. The two basal joints are com- 
pacted together as in the female. The antenne diminish very 
slightly in diameter 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 cylin- 
dric or slightly tapering towards its tip, and consists of seven joints 
beside the terminal one, which (viewed from beneath, vide fig. ¢,) 
consists of a transversely oval joint, giving off two robust process- 
es, 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 brown- 
ish-black color, more or less widely marked at the sutures with 
pallid fulvous or smoky whitish 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 con- 
tinues but a very short time, I infer from the following data. A 
number of wheat plants, containing pup, were transplanted into 
a box of earth, April 21st, and inspected daily. On the morning 
of May Ist, about half of them were found to have sent out the 
perfect fly within the preceding twenty-four hours. On repairing 
to the field whence these plants were taken, the fly was found to 
be out in large numbers. At every step, a dozen or more would 
* How well the engraver has executed his task will be obvious by passing 
a magnifier over the plate. The joints of the tarsi in fig. 3, and other mi- 
nute details, scarcely, if at all perceptible to the naked eye, will then be dis- 
tinetly recognised. 
