752 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



and with an exceedingly gentle sinuous curve, turning upward apically, 

 terminates a little way beyond the first longitudinal vein ; the third 

 longitudinal vein originates from the first as far before the origin of the 

 second longitudinal vein as the distance apart of the tips of the first 

 and second longitudinal veins, and running at first parallel and almost 

 as close to it as the first longitudinal vein to the apical half of the costal 

 margin, but distinctly separate throughout, it diverges slightly from it 

 at the middle of the wing and terminates at the lower part of the apex 

 of the wing, curving downward more strongly toward the margin ; at 

 the middle of the divergent part of its course, which is very regular, it 

 emits abruptly a superior branch, which afterward curves outward and 

 runs in a very slightly sinuous course to the margin, curving upward as 

 it approaches it. The fourth longitudinal vein is seen to start from the 

 root of the wing, and runs in a straight course until it reaches a point 

 just below the origin of the second longitudinal vein, where it is connected 

 with the vein below by the anterior basal transverse vein, and then 

 bends a little downward, running nearly parallel to the third lougitudinal 

 vein, but continuing in a straighter course, terminates on the margin 

 at nearly the same point ; these two veins are connected by the small 

 transverse vein midway between the anterior basal transverse vein and 

 the forking of the third longitudinal vein ; the fourth longitudinal vein 

 is connected by the posterior transverse vein (which is scarcely as long 

 as the small transverse vein) with the upper apical branch of the fifth 

 longitudinal vein just beyond its forking, or opposite the forking of the 

 third longitudinal vein ; the fifth longitudinal vein forks previously to 

 this, emitting a branch barely before the point where the anterior basal 

 transverse vein strikes it, so that the branch almost aj^pears to be a 

 continuation of the transverse vein ; and previous to this it has a dis- 

 tinct angle, where another vein is thrown off at right angles, directly 

 opposite the upper extremity of the anterior basal transverse vein, and 

 beyond the origin of the third longitudinal vein ; the basal half only of 

 the sixth longitudinal vein can be seen, but its direction shows that it 

 unites with the. lowest branch of the fifth at its apex, as in Dasyj)ogon. 

 All the cells throughout the wing are exceedingly narrow. 

 Length of wing G.TS"""^; probable breadth l.e"^"^. 



SYEPHID^. 



Milesia quadrata. — A specimen (No. 14691) in a fine state of preserva- 

 tion, although not perfect, and with most of the neuration of the wing 

 concealed under hard flakes of stone which cannot be whollj^ removed, 

 was found by Dr, Hayden at the "Petrified Fish Cut", Green Kiver. It 

 is the larger fly alluded to in Dr. Hayden's Sun Pictures of Rocky 

 Mountain Scenery, j). 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, promi- 

 nent, half as broad as the head, and half as long as broad. Thorax 



