54 D1PTERA OF NORTH AMERICA. [PART III. 



3. CORMOCARIS Lw. 



Charact. — Eyes round; cheeks very broad ; face in the profile strongly 

 projecting, very much retreating interiorly, not carinate. 



Hairs on the body comparatively long ; thoracic dorsum hairy 

 and bristly as far as its anterior portion. 



Antennae short ; the rounded oval third joint hardly as long as 

 the second. 



First longitudinal vein bristly at its end only. 



Gray species, the abdomen and thorax of which are without any 

 picture, and the wings dusky and somewhat spotted along the an- 

 terior margin. 



Typical species : bucephala Meig. 



4. Pteroposctla Lw. 



Charact. — Eyes small, rounded oval ; cheeks broad ; front very much pro- 

 jecting. 



Hairs on the body of the usual length ; the middle of the thorax 

 bristly on its hind portion only. 



The rounded third joint of the antennae short ; the second like- 

 wise short. 



The first longitudinal vein is hairy upon its whole length. 



The coloring of the body is gray ; the picture of the wings is not 

 unlike that of Idana marginata Say. 

 Typical species: lamed Schrk. 



5. Ptilonota Lw. 



Charact. — Eyes elongated oval ; front but little projecting. 



Thorax bristly upon its middle, as far as its anterior portion. 

 The third antennal joint rounded oval ; the second shorter. 

 The first longitudinal vein bristly at its end only. 



Cinereous-gray species, the thorax of which is marked with 

 four somewhat darker longitudinal lines; the picture of the wings 

 consists of large blackish spots ; in several species these spots are 

 so much confluent that the picture of the wings can almost be 

 called guttate. 



Typical species : centralis Fab. 



6. Ortalis Fall. 



Charact. — Eyes rather large, elongate oval; front only moderately pro- 

 jecting. 



