Dll'TEKA-SVKl'HID.i;. of) 7 



throughout I!M' length of the latter, which originates from the second some 

 distance before the middle of the wing; the small transverse vein between 

 tin- third and fourth longit idinal veins lies just beyond the middle of tin- 

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

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

 and renders the discal and second posterior cells . .1' about equal length 

 Tin- abdomen is apparently lighter colored than the thorax, regular"! \ 

 obovati , as broad as the thorax, and longer than it, its terminal t fifth i seg- 

 nient small, the others large and subequal. 



Length of thorax and scutellum, 4""": breadth of same, 2.75""": length 

 of abdomen, 4.5""": breadth of same, 2.75"""; length of wing, G.5 nim ; breadth 

 of same, 2.25 mm . 



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

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

 verv difficult to trace in certain places. 



(Jreen River, Wyoming. One specimen, No. 146% (Dr. F. V. 

 i laydeli). 



Family SYRPHID^E Leach. 

 MILESIA Latreille. 



MlI.KSIA QUADRATA. 



I'l. '., Fig. i;j. 



, ,, ,,1-lrata Scii'M., Hull. U. S. Geol. Geosr. Surv. Terr., IV, 75'J-75;t (1878) ; Williot., Syo. N. A. 



Syrph, '^81, 283 



A >pei-iintMi in a fine state of preservation, although not perfect, and 

 with must, of the n (.Miration of' the wing concealed under hard flakes of s' 

 which can not \>,- wh >\\\- removed, was found by Dr. Ilayden at the "iVt- 

 rilied Fish ("nt," (Jreeii River. It is the larger fly alluded to in Dr. 

 Ila\ den's Sun Pictures,,!' K'ocky .Mountain Scenery, page 98. The In -ad 

 and thorax are black, the head lar^e. nearly as broad as the thorax, the e\ es 

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

 verv 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. \Vings 

 .sur[iass'mg sli^htlv the abdomen; the.third longitudinal vein nri^i' 

 from the second in the middle of the win^, is ver\' gcntlv arcuate (the 

 convexity l).ickw.ird) in its outer half, and appears to terminate just above 



