286 T. D. A. Cockerel!— A New Fly. 



noticeable bending- ; on level of ending of first longitudinal, 

 the third and fourth are 425 apart, and the third 595 from the 

 second. 



In red shale (Eocene), Green River, Wyoming, a specimen 

 preserved in lateral view, with its reverse ; in Yale University 

 Museum, collector unknown. 



By the form of the auxiliary vein (ending on costa beyond 

 the cross-vein), and the points of union of the longitudinals, as 

 well as the shape of the abdomen, this agrees with the genus 

 Sackenia Scudder, based on a species (S. arcuata Scudd.) from 

 Chagrin Yalley, White River, Colorado. However, with the 

 exception of the auxiliary vein, it might as well be a Myce- 

 topMla of the type of 31. nodulosa Williston.*" The third and 

 fourth longitudinals appear to agree exactly with Myceto- 

 phila, and do not resemble so much those of the original 

 Sackenia. The fifth and sixth would do about equally well 

 for either. The antennae, if not broken, are not so long as in 

 type Sackenia. 



From all the other Mycetophilidse known from the Green 

 River shales, excepting Sciophila hyatti, this is readily dis- 

 tinguished by its larger size. The Sciophila differs in the 

 venation, the second longitudinal vein being much more widely 

 separated from the first, and ending practically at the tip of the 

 wing. 



Univ. of Colorado, Boulder, Colo. 



* Trans. Ent. Soc, Lond., 1896, pi. viii, f. 20. 



