174 THE CANADIAN ENTOMOLOGIST. 



Hub. — Miocene shales of Florissant, Colorado, Station 14 (7^ D. A. 

 Cockerel/, July 8, 1906). The genus Mkrosiylum, Macqiiart, has at 

 present four species in our fauna ; two from Dallas, Texas ; one from 

 Pecos River, on the borders of Texas and New Mexico, and Kansas; and 

 one from Mexico. The fossil is named after Dr. W. M. Wheeler, in 

 recognition of his important contributions to dipterology, and in remem- 

 brance of the fact that he was present when it was found. 



Prodacaiithus Fhiladelphicus, Macq. (specimen from Mesilla Park, 

 New Mexico, caught preying upon a honey-bee), compared with M. 

 Wheeler i, shows the folio wmg important differences in the venation : 



1, The cell in the forks of the radial sector is conspicuously longer 

 and narrower. 



2, The apex of cell ist Vg (Comst.) is rather broadly contiguous with 

 the base of cell V^, or, in other words, the lower branch of the media is 

 sharply angled at the base, the point emitting the cross-vein to cell V3. 



3, Cell V3 (enclosed within the branches of the cubitus, according to 

 my view) is cuneiform, pointed basally, but broadly obliquely truncate 

 apically, and connected with the margin by only one nervure. 



Dialysis revelata, n. sp. (Leptid?e). 



Length, 1873 mm.; proportions about as in D. rufithorax, Say, 

 except that the abdomen is somewhat longer ; head small, diam. 2 mm. 

 or a fraction over, appearing black ; thorax reddish-brown (perhaps 

 ferruginous in life), diam. 4 mm.; abdomen pale reddish-brown, with 

 whitish bands at the bases of the segments, the second and third especially 

 having about the basal half whitish ; wings ample, about 13^3 mm long, 

 the nervures pale ferruginous ; anterior legs pale reddish ; middle and 

 hind femora dark brown or black, but their tibiae and tarsi paler ; length 

 of hind femora about 6 mm., of middle femora, 5^ or a little more. 



Venation like that of D. elo/igata, Say {dissimilis, Walker), as figured 

 by Williston from Austen's drawing (Kans. Univ. Quarterly, April, 1895, 

 p. 264), except as follows : 



1. The subcosta reaches costa about 8 mm. from base of wing, thus 

 considerably beyond the middle. 



2. Vein R2,3 (following the nomenclature of Comstock and Need- 

 ham, Amer. Naturalist, XXXII, p. 233) is strongly bent downwards where 

 R^^- leaves it. (Such a bend is slightly indicated in Leptis.) 



3. The discal cell is longer; on its upper side, the part beyond the 

 cross-nervure to the radius, is much more than twice as long as that 

 before it, 



