DIPTERA, 425 



third segment either with or without a style or bristle, but not 

 divided into subsegments. 



C. Antennse consisting apparently of a single globular segment 

 bearing a long bristle ; wings with some stout veins near the 

 costal margin and other weaker ones extending across the 

 wing unconnected by cross-veins (Fig. 581). p. 475.Phorid.«. 

 CC. Flies that do not present the type of venation represented 

 by Figure 581. 



D. Cells V and first V2 not separated (see Fig. 571 for an ex- 

 ample of this type). 



E. Vein III with a knot-shaped swelling at the point of 

 separation of veins III2 + 3 and III4 + 5; the cross-vein 

 III-V at or near this swelling; no suture immediately 



above the antennae, p. 467 DoLiCHOPODiDiE. 



EE. Vein III with or without a swelling at the point of 

 separation of veins III2 + 3 and III4 + 5; the cross-vein 

 III-V more remote from base of wing; a suture immedi- 

 ately above the antennae, p. 479 MusciD^. 



DD. Cells V and V2 separate. 

 E. Vein III four-branched. 

 F. Venation intricate, due to an unusual anastomosing of 



the veins (Fig. 555). p. 459 Nemistrinid^. 



FF. Venation not of the type represented by Figure 555. 

 G. Vertex of head distinctly hollowed out between the 

 eyes (Fig. 557); eyes never contiguous, p. 460. 



ASILIDiE. 



GG. Vertex of head not hollowed out between the eyes; 

 eyes often contiguous in males. 



H. Alulets very large, p. 458 ACROCERiDiE. 



HH. Alulets small or rudimentary. 

 I. Cell V3 present. 

 J. Vein III5 ending before the apex of the wing 



(Fig. 562). p. 462 Apiocerid^. 



JJ. Vein IIIb not ending before the apex of the 



wmg. 



K. Empodia pulvilliform, i.e., with three mem- 

 branous lobes beneath the tarsal claws (Fig. 



495). p. 456 LEPTIDiE. 



KK. With only two membranous lobes beneath 



the tarsal claws, p. 464 Therevid^. 



II. Cell V3 obliterated by the coalescence of veins 

 Vgand VIIi. 



