542 TERTIARY INSECTS OF SORTH AMERICA. 



Family SCIOMYZID^E Fallen. 

 SCIOMYZA Fallen. 



SdOMYZA REVELATA. 

 PI. 3, Figs. 3-6. 



Sdoimi~n m-elata Scudd., Rep. Progr. Geol. Surr. Can., 1875-187G, 275-276 (1877); 1876-1877, 458- 



459 (1878). 



Three specimens are to be referred to this species. Although each of 

 them is rather imperfect, the collocation of the fragments enables us to recon- 

 struct all parts of the wing. The head was about one-fifth the size of the 

 thorax ; the thorax broadly vaulted, abruptly arched in front, somewhat 

 depressed above ; the wings were a little more than twice as long as broad 

 with the costal border gently arched, the apex slightly angulated and the 

 lower margin pretty regularly convex, bent but rounded at the axillary 

 angle; the membrane and the castaneous veins as well are covered not very 

 profusely with delicate microscopic hairs, distributed with great regularity 

 and about 0.02 mm apart; the costal vein is setose throughout the upper 

 margin, and extends to the fourth longitudinal vein, although it is but faint 

 at the extreme tip or on the lower third of the space between the third 

 and fourth longitudinal veins ; the auxiliary vein is weak, but distinctly 

 separated from the first longitudinal vein from its very base, terminating at 

 the middle of the basal half of the costa; the transverse shoulder vein is 

 exactly transverse, very faint, and lies a little beyond the base of the basal 

 cells; the first longitudinal vein is bare save the pubescence, and apparently 

 terminates just within the small transverse vein ; the latter lies as far before 

 as the large transverse vein lies beyond the middle of the wing and is mid- 

 way between the basal cells and the large transverse vein ; the second and 

 third longitudinal veins are nearly straight, slightly sinuous and subparallel 

 throughout, but at their tips diverge from each other: the third longitudinal 

 vein is regularly though but slightly arched beyond the small transverse 

 vein, and strikes the very apex of the wing; the fourth longitudinal vein 

 is made up of three perfectly straight subequal parts, slightly bent at the 

 transverse veins ; the larger transverse vein is straight, nearly perpendic- 

 ular to the costa; it is about half the length of the middle portion of the 

 fourth longitudinal vein, and its lower extremity is nearer the margin of the 

 wing (following the course of the fifth longitudinal vein) than its own 



