DIPTERA. 425 



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

 divided into subsegments. 



C. Antennae 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/E. 

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

 by Figure 581. 



D. Cells V and first V 2 not separated (see Fig. 571 for an ex- 

 ample of this type). 



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

 separation of veins III 2 + 3 and III 4 + 5; the cross-vein 

 1II-V at or near this swelling; no suture immediately 



above the antennae, p. 467 DOLICHOPODID^E. 



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

 separation of veins III 2 + 3 and Ilh + s; the cross-vein 

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

 ately above the antennas, p. 479 MusciD^E. 



DD. Cells V and V 2 separate. 

 E. Vein III four-branched. 



F. Venation intricate, due to an unusual anastomosing of 



the veins (Fig. 555). p. 459 NEMISTRINIDTE. 



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. 



ASILID.E. 



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

 eyes often contiguous in males. 



H. Alulets very large, p. 458 ACROCERID.E. 



HH. Alulets small or rudimentary. 



I. Cell V 3 present. 



J. Vein III 6 ending before the apex of the wing 



(Fig. 562). p. 462 APIOCERID^:. 



JJ. Vein Ills not ending before the apex of the 

 wing. 



K. Empodia pulvilliform, /.<?., with three mem- 

 branous lobes beneath the tarsal claws (Fig. 



495). p. 456 LEPTID^E. 



KK. With only two membranous lobes beneath 

 the tarsal claws, p. 464 THEREVID^. 



II. Cell V 3 obliterated by the coalescence of veins 

 V, and VIL. 



