FAMILY DOLICHOPID.T: THE LONG-HEADKD FLIES 217 



8. Thorax almost as broad as long; head wider than hig-h; the front 



deeply excavated from anterior view; face wide (48, 51). 



* Mesorhaga Schiner 

 Thorax and head different 9 



9. Basal segment of the posterior tarsi with stout bristles above (24, 



42, 57 ) t Dolichopus Latreille 



Basal segment of the posterior tarsi without bristles above 10 



10. Mesopleura produced as a finger-like strip along the posterior edge 



of the anterior coxse (20) J Liancalus Loew 



Mesopleura normal, not produced as above 11 



11. Males 12 



Females 64 



12. Hypopygium long, extending forward under the venter 13 



Hypopygium short, only the lamellae sometimes extending foi'ward. . . 25 



13. Arista long pubescent, sub-plumose 14 



Arista quite short pubescent or bare 16 



14. Third antennal segment very large, acuminate Leptocorypha Aldrich 



Third antennal segment normal, short and somewhat pointed 15 



15. Face wide below, roof -like over the mouth, concave in the middle 



(22, 25, 46, 77) § Pelastoneurus Loew 



Face narrow, especially below (66, 79) Sarcionus Aldrich 



16. About the posterior third of the mesonotum concave or flattened 17 



Mesonotum flattened only immediately before the scutellum 20 



17. Second antennal segment prolonged along the inner side of the third 



(67, 73) Coeloglutus Aldrich 



Second antennal segment not prolonged along the third 18 



18. Hypopygium pedunculate, at least not sessile, reaching almost to the 



base of the abdomen 19 



Hypopygium sessile, the basal part not reaching half way to the base 

 of the abdomen although the lamellae may do so (45, 81). 



^Paraphrosylus Becker 



19. Third and fourth veins strongly converging apically, the distance 



between them at their apices not more than half as great as oppo- 

 site the posterior crossvein; bristles rarely yellow (63, 86). 



I Medeterus Fischer 

 Third and fourth veins separated apically by at least two-thirds the 

 distance separating them opposite the anterior crossvein; hair and 

 bristles yellow (31, 59) °Thrypticus Gerstsecker 



20. The face hangs down apron-like below the eyes (15, 38). 



0Polymedon Osten Sacken 

 The face is not produced as a long, thin ribbon 21 



* Van Duzee, 1917, Ent. News, xxviii, p. 123. 



t Van Duzee, Cole and Aldrich, 1921, Bull. 116, U. S. N. Mus. ; Van Duzee and Curran, 

 1934, Amer. Mus. Novit. Nos. 683, 684. 



i Van Duzee, 1917, Ent. News, xxviii, p. 126. 



§ Van Duzee, 1923, Ann. Ent. Soc. Amer., xvi, p. 30. 



^ Van Duzee. 1924, Pan-Pac. Ent., i, p. 73. 



II Van Duzee, 1928, Psyche, xxxv, p. 38. 



° Van Duzee, 1921, Psyche, xxviii, p. 124. 



Van Duzee, 1927, Ann. Ent. Soc. Amer., xx, p. 123. 



