250 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 57. 



Family BLEPHAROCERIDAE. 



PHILORITES PALLESCENS, new species. 



Plate 34, fig. 6. 



Length (excluding proboscis) 3 mm. ; proboscis stout, directed for- 

 ward, about 1 mm. long; wings about 3.5 mm. long. Dark fuscous 

 or black, the legs brow^n; wings dilute brown. 



Type. — U.S.G.S., Winchester F. 17-4, spring at head of Little Duck 

 Creek, Colorado; collected by D. E. Winchester and H. R. Bennett. 



Holotype.— Cat. No. 66571, U.S.N.M. 



This is preserved in exactly the same position as the type of 

 PMlorites joJiannseni Cockerell, the position of the wings, one elevated 

 the other depressed, evidently resulting from pressure on the elevated 

 thorax. The details of the venation of P. pallescens can not all be 

 made out, but the strong Rj and R4+5 leaving it, are as in P. johann- 

 seni, and the media is also very distinct. In general, the flies are so 

 similar that they are surely congeneric, but P. pallescens is readily 

 distinguished by its smaller size and much paler wings. 



On the same piece of rock is an apparent ant, of the size and general 

 appearance of Scudder's Lasius terreus; but it has neither wings, legs 

 nor antennae. It is in any event not a Lasius. 



Oestrid larvae, Lithohypoderma ascarides (Musca ascaiides Scudder) 

 are also found, in great abundance, at Station F 17-4. 



Family ASILIDAE. 



ASILOPSIS, new genus. 



Small flies apparently related to Asilinae or Laphriinae; marginal 

 cell closed far from end of wing; base of marginal obtuse, and the part 

 basad of basal end of first submarginal much longer than that apicad of 

 it; first basal on first submarginal scarcely longer than anterior cross- 

 vein; discal cell elongated, with anterior cross-vein far toward the 

 base; two submarginal cells, the second less than half as long as 

 first; second posterior cell somewhat swollen toward base; fourth 

 posterior apparently open. 



Type. — Asilopsis fusculus, new species. 



ASILOPSIS FUSCULUS, new species. 



Plate 35, fig. 3. 



Wing (the base not preserved) probably about 9 mm. long; uniform 

 dilute fuscous, except that there is a darker cloud in apical part of 

 marginal cell; the following measurements are in microns: apical 

 petiole of marginal cell, 1760; base of first submarginal to base of 

 marginal, 2480; first basal on first submarginal, 160; discal on first 

 posterior, 1570; first basal on fourth posterior, 1920. 



