756 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



DOLICHOPID^. 



DolicJiopiis sp. — A specimen and its reverse (Nos. 4124, 4148) is to be 

 referred to this family by the structure of the abdomen and its general 

 aspect. The wings and head, however, are wanting. The thorax is 

 globose, well arched, and, lilie the abdomen, of a light brown color, and 

 ornamented with scattered, bristly, black hairs. The tip of the abdomen 

 is recurved beneath. The length of the fragment is 3.65^™. 



TACHINID^. 



TacMna sp. — To this is referred provisionally a small but stout and 

 densely hairy fly (No. 48^, obtained by Mr. Eichardson), with thick, 

 slightly tapering abdomen, broadly rounded at the tip, long wings with 

 heavily ciliated costal margin, the auxiliary vein terminating a little 

 before the middle, and the first longitudinal vein not very far before 

 the tip ; the other veins of the wing cannot be determined. The legs 

 are pretty stout and densely haired. About the fly are scattered many 

 arcuate, tapering, spinous hairs 0.7™™ long, evidently the clothing of 

 the thorax. 



Length of body 4™™ ; breadth of thorax 1.25™™; length of wings 4™™ (I), 

 of hind femora 0.6™™ ; hind tibise 1.25™™ ; hind tarsi 1.25™™ (?). 



SCIOMYZID^. 



Sciomyzaf manca. — This fly, extremely abundant in the Green Eiver 

 shales — in fact, outnumbering all the other Di]^tera together — is tempo- 

 rarily placed in this genus, because its characters seem to agree better 

 with those of the family Sciomyzidce than of any other ; yet it cannot 

 properly be placed in any of the genera known to me. I should be 

 inclined to place it near Blepharoptera in the Selomyzidce, but all the 

 tibisB are bristled througliout. Its general appearance is that of the 

 Uphydrinidw, but the bristly surface of the middle tibise would allow us 

 to place it only in the Notiphilina, from which it is excluded by the 

 want of pectinations on the upper side of the anteunal bristle. The 

 want of complete neuration prevents me from designating it at present 

 by a new generic name, which it can hardly fail to require as soon as 

 that is known ; only two or three of the three score specimens before 

 me have any important part of the wings, and this constant frag- 

 mentary condition of the fossils has suggested the specific name. The 

 genus in which it would fall may be partially characterized as follows: — 

 Body compact, stout ; the head comparatively small, perhaps one-third 

 the bulk of the thorax, about three-fourths its width, with large, naked 

 eyes, the front between them nearly equal and pretty broad, obliquely 

 sloped and slightly tumid on a side view, so as to project considerably 

 below ; a few curved bristles project from its summit. Antennae with 

 the flagellum subglobose, scarcely longer than broad, much larger 

 than the joints of the scape, and bearing at its tip above a curved, 



