DIPTEEA-MUSCID.E. 553 



MUSCA sp. 



PI. 5, Figs. 106, 108. 

 2Iusca sp. Sciidd., Bull. IT. S. Geol. Geogr. Siirv. Terr., Ill, 7.-)7 (1877). 



A third species is represented by three or four contracted skins, wliicli 

 are too uncharacteristic to n;iine, though it may be seen that tliey are distinct 

 from the othei's. As preserved tliey are ahiiost bhick ; the skin is much 

 wrinkled and smooth ; the body pretty regularly and bluntly obovate, nearly 

 twice as long as broad ; at the end of one, two colorless oval patches lie 

 united, side by side, pressed against the extremity, *and doubtless represent 

 the head, and prove it to be different from the other species ; it is, however, 

 impossible to say what its affinities may be 



Length of body, 8.5""" ; breadth, 4""". 



Chagrin Valley, White River, Colorado. (W. Denton). 



MuSCA HYDROPICA. 



PI. .->, Figs. 72, 92, 93, 107. 



Musca hydropica ScmUl., Bull. U. S. Geol. Geogr. Surv. Terr., Ill, 757-758 (1877). 



A fourth species is represented b}' two bodies and a skin, which present 

 an entirely different appearance from the preceding three species, but which 

 may temporarily be given the same broad generic name. In this species the 

 form, even when contracted, is far more elongated than in the others; the body 

 is nearly five times as long as broad, is broadest just behind the roundly 

 pointed head, tapers rapidly toward it, but gently posteriorly to the middle, 

 behind which it is equal. In the skin tlie part of the body preserved is 

 equal and very broad, excepting toward the head, where it rapidly narrows, 

 the head being well rounded or slightly produced ; the mouth parts, instead 

 of being withdrawn a little from the front extremity of the body, as in the 

 species already described, lie at its very boundar}-, and the blades are par- 

 allel instead of posteriorly divergent. The integument is covered rather 

 profusely with very short, conical, tapering hairs, scarcely more than twice 

 as long as their breadth at base. The larva is very distinctly banded with 

 darker and lighter colors, as the empty skin shows, the posterior third of 

 each segment being occupied by a very dark band, darkest on the dorsal 

 surface, while a faint pale transverse line breaks the anterior portion into 

 two equal halves of the same width as the blackish band. 



