748 BULLETIN UNITED STATES GEOLOGICAL SUKVEY. 



stigma of the wiug is lost by the incompleteness of the preservation. 

 The legs are very slender and delicately hairy throughout, with no 

 sign of spurs, although it should be remarked that the extremities of 

 the tibiffi are not well preserved. Length of middle femora 5.25™"^ ; 

 middle tibiiie 4.5™™; hind femora 5.75™™ ; hind tibice S.S""™. Chagrin 

 Talley. 



Another specimen is a female, with remnants of wings, having most of 

 the veins scarcely traceable ; enough of the right wing remains to be 

 sure that it is this species, with which the size agrees. Fossil CaQon. 



Still another is similarly preserved ; but, on account of the partial 

 folding of the wing, no stigma can be seen, and the first longitudinat 

 vein seems to unite, or almost unite, with the second, so far from the 

 branching of the latter, that I was at first inclined to separate it, but 

 the difference proves to be very slight. The antennse of this specimen 

 are pretty well preserved, but so bent as not to allow of direct measure- 

 ment; the size agrees well with other specimens, although it is slightly 

 smaller than the second specimen mentioned, which, however, is rather 

 larger than the average. The specimen is a female. Fossil Caiion. 



A head preserved on the same stone as the last specimen probably also 

 belongs to this species. 



In the last specimen to be mentioned, we have the upper surface of 

 an abdomen of a male Bicranomyia, apparently of this species, twisted 

 so as to present a lateral view of the tip, showing the structure of the 

 under surface of the appendices. The under inner edge is evidently thick- 

 ened, and a slight hook projects a little beyond the broad lobe ; as the 

 lobe itself is preserved in a different view from what holds in the other 

 specimens, and therefore has a slightly different contour, the specimen is 

 judged to belong to this species only from the size of the abdomen and of 

 its anal lobes. Chagrin Valley. 



Dicranomyia primitiva. — Two specimens, a little smaller than D. stig- 

 mosa, but still more closely resembling D. pubqyennis, together with a 

 third, which is simply a body, to which is attached the costal outline of 

 a wing, and near which lies a leg, represent the female of this species. 

 The two first mentioned are rather faintly preserved, but permit the 

 venation to be traced with certainty, though with difficulty, and with one 

 of them a portion of a detached (middle or hind) leg may be seen. The 

 neuration of the wing differs from that of D. sUgmosa in the shape of the 

 discal cell, the inner border of which is straight, and strikes the incom- 

 plete fifth longitudinal vein exactly where the lower cross-vein strikes it, 

 so that the two are continuous, and }produce no break of direction in the 

 fifth longitudinal vein. The auxiliary vein is not preserved, and there 

 is no adventitious vein in the stigma, which otherwise is as in that 

 species. The wing is not so slender as in D. sUgmosa. Length of body 

 5.5™™ ; wing 5,5-6™™ ; femur 5™™ ; tibia 5.75™™; first two joints of tarsi 

 3.5™™. The measurements of the leg are doubtful. Fossil Caiion. 



Another poorly preserved specimen, which, by the structure of the 



