646 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



posterior or inferior branch of third, 672 ; apical width of first posterior 

 cell, about 336; apical width of second posterior, about 320. 



Wilson Ranch, Miocene shales of Florissant {H. F. Wickham). 

 This appears to be a quite ordinary species of Emyis. These are the 

 first Empididse to be described from Florissant. 



Empis florissantana. Costo-apical region of wing. 



Empis florissantana. Discal cell and adjacent parts. 

 Plecia axeliana n. sp. (Bibionidae). 



9. Length about 8. .5 mm., wing 9 mm.; thorax black with the 

 mesothorax apparently red; abdomen banded dark and light, the 

 light bands wider than the dark; wings reddish hyaline, suffusedly 

 darker in costal region; head small, about 1.25 mm. diameter; 

 venation normal. 



The following measurements are in microns: depth of marginal 

 cell at level of anterior cross-vein, 480; depth of submarginal cell at 

 level of end of second vein (so-called anterior branch of third), 480; 

 distance from end of second vein to end of third, about 1,760; dis- 

 tance in a straight line from base of marginal cell to separation of 

 second vein from third, 2,880; length of the rather oblique anterior 

 cross-vein, 272; lower end of anterior cross-vein to fork of fourth, 

 752. 



Wilson Ranch, Miocene shales of Florissant {H. F. Wickham). 

 Much larger than P. melanderi Ckll. (d^), with the abdomen quite 

 differently marked; but in view of the sexual dimorphism in this 

 family, it may be the female of melanderi. I have given it a name 



