932 CHARLES PauL ALEXANDER 
Genus Trimicra Osten Sacken (Gr. three + small) 
1861 Trimicra O. S. Proc. Acad. Nat. Sci. Phila., p. 290. 
Trimicra is a small genus of crane-flies, including about fifteen described 
species found in most parts of the world, almost all being forms of moderate 
size and obscure coloration. These various species bear a close resem- 
blance to one another and are hard to distinguish specifically. 
Bergroth and other European writers consider the genus Trimicra as 
being the same as Psiloconopa Zetterstedt, but at this time the writer 
is not entirely willing to accept this view. 
Beling (1879:48) described what he took to be the larva of one of 
these flies, and in his key to the larvae of crane-flies (1886:206) he 
included it in close proximity to the Pediciini. As mentioned elsewhere 
in this paper, it is highly probable that Beling described a pediciine larva, 
but by an accident had larvae of Trimicra in his breeding jars, the latter 
larvae emerging first and confusing the author. 
Gerbig (1913:161-163) describes the real larva of Trimicra pilipes 
(Fabr.), the best-known species of the genus. It is found along the 
margins of flowing streams with muddy banks. It is a dark-colored 
larva, about 15 millimeters in length and about 2 millimeters in 
diameter. The skin of the body is similar to that of the larvae in the 
typical subgenus of the genus Limnophila, being covered with chitinous, 
hairlike projections, which in Trimicra are longest on the dorsal surface of 
the body. On each segment there are solitary elongate bristles, above and 
below each of which is a gland. The spiracular disk (Plate LX XIII, 395) 
is surrounded by five nearly equal lobes, which have the inner faces 
marked with equal blackened, chitinized areas. On the lateral margins 
of each lobe, but occupying only the distal part of the lobe and not con- 
tinuous around the disk, is a fringe of moderately long hairs. At the 
tip of each ventral lobe are two bristles, and at the tip of each lateral 
lobe is a single bristle, these being inserted outside the line of hairs and 
surrounded by a bright circular area. The ventral sensory bristles found 
in some crane-fly larvae (as Tipula variipennis) are lacking. At the 
base of the lateral lobes are the spiracles, which are generally similar to 
those in the subgenus Limnophila. Gerbig discusses in detail the structure 
of the spiracles, the felt chamber, and the musculation of this region 
of the body. 
