648 PROCEEDINGS OF THE ACADEMY OF [DeC, 



of the small cell Ri, and is about the middle of that cell, which is 

 quite long, as in M. ohliqua (Say). The apical end of cell R has its 

 upper face (above separation of lower branch of radius from radio- 

 medial cross-vein) 128 microns long, and the lower face (radio-medial 

 cross-vein) 192 and more oblique; this is almost as in M. maxima Joh. 

 Miocene shales of Florissant, Wilson Ranch (Wickham). Larger 

 than the fossil M. cockerelli, and differing in coloration, details of the 

 venation, and the proportions of the legs. It appears to be very close 

 to the living M. mendax Joh., a species of the Pacific coast region. 



Asilus wickhami n. sp. (Asilidse). 



Length 18.5 mm., of which 13.25 is abdomen; wings about 11 mm.; 

 middle femora 3 mm., hind femora 4. Antennae normal; the head 

 and thorax were apparently black, the abdomen paler, somewhat 

 darker dorsally than ventrally; legs without conspicuous bristles, 

 tarsi thick;, wings clear, nervures ferruginous. Bristles on the legs 

 can be seen with the compound microscope, but they are pale or 

 reddish, not black as in most species, and so are easily overlooked. 



As in A. peritulus Ckll., the veins at the end of the second basal 

 and fourth posterior cells form a cross; but in some other respects 

 the venation differs from that of A. peritulus as follows: 



(1) Marginal cell not so narrow at end. 



(2) Sides of second submarginal beyond base parallel until near 

 apex, when they gradually diverge; in A. peritulus the sides have a 

 gentle double curve. 



(3) Second posterior cell broader at base. 



(4) Anterior cross-vein about middle of discal cell ; i.e. , 1 ,440 microns 

 from base and 1,330 from apex. 



Wilson Ranch, Miocene shales of Florissant {H. F. Wickham), 



