DIPTERA— CBIEONOMIDiE. 579 



upward, its tip rather indicating the specimen to be a male. The legs are 

 well preserved, and the wings so far as their venation can be made out 

 indicate a Chironomus. One antenna is preserved and is very slender indeed, 

 about a third or a quarter the width of the front tibia and about as long as 

 the eye; it is not shown on the plate and is obscure from its crossing the 

 front tibia; its basal joint is rounded ovate, twice as stout as the stem, 

 which is equal, with a blunt tip; no hairs can be detected except some exces- 

 sively delicate ones close to the base, the only portion excepting the tip which 

 is not obscured by the tibia; all the joints of the stem appear to be cyHn- 

 drical and in no way moniliform. The legs are of nearly equal length. The 

 tibife are slightly longer than the femora and of the length of the thorax; 

 the first joint of the tarsi is less than half as long as the tibia, and the 

 remainder of the tarsus a little more than half as long again as the first 

 joint. The femora and tibiae are sparsely clothed with very short delicate 

 hairs, and the tibiae and tarsi, and especially the latter, have in addition a 

 few inferior rows of distant short delicate spines, a pair of which, as short 

 as the others, are apical in the tibiae, and perhaps also in the tarsal joints. 

 The whole body is uniformly testaceous, slightly infuscated by the sparse 

 clothing of short fine hairs. 



Length of body, 3""" ; of thorax, 1.2-°" ; of legs, about 3.5°"°. 



Grreen River, Wyoming One specimen, No. 10 (Dr. A. S. Packard), 



Chironomus depletus. 



PI. 5, Fig. 62. 



Chironomus depletus Sciidd., Bull. U. S. Geol. Geogr. Surv. Torr., Ill, 744 (1877). 



A single mutilated specimen of this insect remains, and is doubtffiUy 

 referred to Chironomus. The thorax is moderately robust and the al.ido- 

 men rather plump for a Chironomus. The antennae are broken, and only 

 the costal border of one of the fore wings can be seen ; this shows that the 

 second longitudinal vein terminates in the middle of the apical, and the first 

 longitudinal apparently in the middle of the basal, half of the wing. The 

 legs are moderately long, slender, the tibiae finely spined, the spines 

 arranged on the middle legs in a somewhat verticillate manner, and termi- 

 nating with two or three long spurs ; the femora are rather short, the tibiae 

 considerably longer, but not so long as the tarsi. 



