FOSSIL FLY OF THE FAMILY BLEPHAROCERID^. 263 



That tlie Blepbaroceridae are not of recent origin is suffi- 

 ciently manifest from their characters and distribution ; hypo- 

 thetically, Handlirsch supi)oses them to have arisen as long 

 ago as the Lias. However this may be, it is of much 

 interest to find a representative in the earlier Tertiaries of 

 Colorado, throwing the first actual light on the early history of 

 the group. 



The fossil now described is one of a small series of fossil 

 insects kindly loaned to me by Dr. S. M. Bradbury, of Grand 

 Junction, Colorado. The specimens were found a few miles 

 north of Rifle, Colorado, an entirely new locality for fossil 

 insects. They consist of Coleoptera, Diptera, and Hemiptera 

 (but no Hymenoptera), and occur in a sort of close-grained sand- 

 stone, varying in colour from dull grey to pale ochraceous or 

 creamy. It is probable that they belong to the Green River 

 Series, but they may be referable to the Wasatch. My colleague 

 Professor R. D. George thinks that the rock looks like Wasatch, 

 but the general facies of the insect-fauna recalls that usually 

 ascribed to the Green River. The age is considered to be 

 Eocene. 



When I first examined the specimen, I thought it must 

 belong to the Simuliidae ; but a closer scrutiny indicated that 

 this was impossible. It did not seem to agree well with any 

 described family ; and being altogether perplexed, I sent a rough 

 sketch to Professor 0. A. Johannsen, of Cornell University. 

 Professor Johannsen replied, suggesting that it might be referred 

 to the Blepbaroceridae, and advising comparison with Apistomyia 

 and Hammatorhina. With this clue I re-examined the fossil, 

 and had little difficulty in determining that it was indeed a 

 Blepharocerid. I found, also, that my original sketch was faulty 

 in several respects, and, so far as I could ascertain, the affinities 

 of the insect were with Bibiocephala and Philorus, although it 

 evidently represented a very distinct genus. Kellogg (Proc. 

 Calif. Acad. Sci., 1903) has divided the Blepbaroceridae into two 

 series, one with, the other without, an incomplete vein (branch 

 of the media) near the posterior margin of the wing. The in- 

 complete vein is present in all of the living North American 

 forms, and is absent principally in the tropical genera. Owing 

 to the conditions of preservation I am not able to quite clearly 

 demonstrate this vein in the fossil, but I believe I can see it, 

 and the probability of its existence is increased by the wide 

 interval between the media and the cubitus, apparently needing 

 such a support. 



From all of the genera in the section having the incomplete 

 vein the fossil is distinguished by the large costal cell, the 

 position of the radiomedial cross-nervure, the long proboscis, 

 and the short legs. 



