DIPTERA 793 



C. Hypopleural bristles absent. Cell R s very slightly or not at all narrowed 



at the margin of the wing. (Anthomyioidea). p.' 863 Anthomyiid^ 



CC. Either the hypopleural or the pteropleural bristles or both present. 

 Cell R,s narrowed or closed. (Muscoidea). 

 D. Both hypopleural and pteropleural bristles present. 



E. Clypeus more or less produced below the vibrissal angles. Like the 

 bridge of a nose. Abdomen not armed with stout bristles. The con- 

 junctivae of the ventral sclerites of the abdomen present, p. 868. 



Ph.\siid^ 



EE. Clypeus flattened, at most slightly produced. Abdomen bearing 

 some stout bristles. The conjunctiva; of the ventral sclerites of the ab- 

 domen not visible. 



F. Clypeus receding and short; the cheeks very broad; vibrissjE 

 located near the middle of the face; antenna short, p. 869. . . . 



Megaprosopid^ 



FF. Clypeus long and never conspicuously receding; the oral margin 

 more or less prominent; vibrissal angles near the oral margin; 

 antennae usually long. 



G. Second ventral sclerite of the abdomen lying with its edges 

 either upon or in contact with the ventral edges of the corre- 

 sponding dorsal sclerite. 



H. Hindermost posthumeral bristle almost always lower (more 

 ventrad) in position than the presutural bristle; body color very 

 frequently metallic green or blue, or yellow; arista plumose. 



p. 869 Callipiiorid^ 



HH. Hindermost posthumeral bristle on a level with or higher 

 (more dorsad) than the presutural bristle; arista bare, pubes- 

 cent, or plumose only on the basal two-thirds; body coloring 

 gray or silvery, tessellated or changeable pollinose. 



I. Fifth ventral abdominal sclerite of the male either wanting 

 or with the caudal margin straight, presutural intraalar 

 bristle rarely present, p. 870 Sarcophagid^ 



II. Fifth ventral abdominal sclerite of the male cleft to beyond 

 the middle. p. 871 Tachinid^ 



GG. Second ventral abdominal sclerite, as well as the others, more 

 or less covered, sometimes wholly, by the edges of the dorsal 



sclerites. p. 871 Tachinid/E 



DD. Either the hypopleural or the pteropleural bristles present; basal 

 bristles of the abdomen reduced; arista plumose to the tip. p. 872. . . . 



MUSCID^ 



TABLE C— DIPTERA IN WHICH THE WINGS ARE 

 WANTING OR VESTIGIAL 



A. Mesonotum with a complete V-shaped transverse suture (Chionea) p. 798. 



Family Tipulid^ 



AA. Mesonotum without a V-shaped transverse suture. 



B. Flies in which the abdomen is distinctly segmented and the two ]ezs, of each 

 thoracic segment are not widely separated. The adults do not live parasitic- 

 ally upon either birds, mammals or the honey-bee. 



C. Nematocerous flies; antenna more or less thread-like and consisting of 

 six or more segments. 

 D. Wings short, strap-like, thickened, and without distinct venation 



{Eretmoptera). p. 802 Chironomid^ 



DD. Wings and halteres wholly wanting (Pnyxa, female) p. 810 



Mycetophilid^ 



CC. Brachycerous flies. 



D. Antennae consisting apparently of a single segment, which bears a 

 long, three-jointed arista, p. 847 Phorid^ 



