586 TEiiTIAEY IKSEOTS OF NOETH AMERICA. 



and excellently preserved, as see Figs. 10 and 12. Dr. Peale brought home 

 nine slabs, numbered 1 to 6, containing ten specimens, with reverses of four 

 of them. Three or four good specimens were also sent me from Twin 

 Creek by Prof. J. S. Newberry, and were then taken for the preceding 

 species. 



Named for the geologist Dr. A. C Peale, who has been quick in the 

 discovery of insect-bearing shales in the West. 



Plecia dejecta. 

 PI. 10, Fig. 17. 



This species is in most respects nearer P. similkameena than P. pealei 

 from the neighboring region to the north, but it is considerably smaller 

 than the former and than most specimens of the latter ; a single well pre- 

 served and neai'ly perfect specimen has been found, in marked contrast to 

 the abundance of P. pealei to the north. As in P. pealei the superior branch 

 of the third superior vein is no longer, or scarcely longer, than the distance 

 from the median transverse vein to the origin of the branch, while, on the 

 other hand, it resembles P. similkameena in that the length of the median 

 transverse vein is double that of the distance from it to the foi-k of the fourth 

 longitudinal vein, represented a trifle too short on the plate. The legs are 

 as in the other species as far as noted. 



Length of wing, 7.5°""; breadth of same, 3"™. 



Green River, Wyoming One specimen. No 8 (Dr. A. S. Packard). 



Family MYCETOPHILIDyE Westwood. 

 SCIARA Meigen. 



SCIARA DEPERDITA. 

 PI. 3, Fig. 17. 

 Sciara deperdita Scndd., Rep. Progr. Geol. Surv. Can., 1876-1877, 457-458 (1878). 



The remains of this species consist of a single perfect wing and the 

 fragments of an eye whose facets are 0.0165"™ in diameter. The wing is 

 oval and regularly rounded, with a somewhat abrupt inner angle, the sur- 

 face covered with microscopic hairs. Judging from Winnertz's descriptions 

 this insect must be more nearly allied to S. ungulata Winn, than to any 



