DIPTERA— SYRPHIDiE. 557 



througlioiit tlie length of the latter, which originates from the second some 

 distance befoi-e tlie middle of the wing; the small transverse vein between 

 tlie third and fourth longitadinal veins lies just beyond the middle of the 

 wing and perpendicular to the costal border, while the large transverse vein 

 between the fourth and fiftli longitudinal veins is perpendicular to the latter 

 and renders the discal and second posterior cells of about equal length. 

 The abdomen is apparently lighter colored than the thorax, regularly 

 obovate, as broad as the thorax, and longer than it, its terminal (fifth) seg- 

 ment small, the others large and suberpial. 



Length of thorax and scutellum, 4™"; breadth of same, 2.76'""'; length 

 of abdomen, 4,5™"'; breadth of same, 2.75'"'"; length of wing, 6.5"""; breadth 

 of same, 2.25""". 



I am indebted to Mr. Edward Burgess for some critical remarks upon 

 the affinities of this fiy, and for a careful sketch of the neuration, which is 

 very difficult to trace in certain places. 



Green River, Wyoming. One specimen. No. 1469t) (Dr. F. V. 

 Hay den). 



Family SYRPHID.C Leach. 

 MILESIA Latreille. 



MiLESIA QUAURATA. 

 ri. 9, Fig. 13. 



Milesia qmirata ScmU., Bull. U. S. Geol. Geosr. Siirv. Terr., IV, 75-2-7r)3 (1878); Willist., Syn. N. A. 



Syrph, asi, a83 (1886). 



A specimen in a fine state of preservation, although not perfect, and 

 with most of the neuration of the wing concealed under hard flakes of stone 

 which can not ba wholly removed, was found by Dr. Hayden at the "Pet- 

 rified Fish Cut," Green River. It is the larger fly alluded to in Dr. 

 Hayden's Sun Pictures of Rocky Mountain Scenery, page 98. The head 

 and thorax are black, the head large, nearly as broad as the thorax, the eyes 

 large, globose, as broad as the summit of the head between them, the front 

 very large, prominent, half as broad as the head, and half as long as broad. 

 Thorax globose, a little longer than broad, largest in the middle. Wings 

 surpassing slightly the abdomen; the third longitudinal vein originates 

 from the second in the middle of the wing, is very gently arcuate (the 

 convexity backward) iii its outer half, and appears to terminate just above 



