DIPTERA 789 



H. Scutellum without spinous protuberances, p. 833 



Xylophagid^ 



HH. Scutellum with two spinous protuberances, p. 834. . . 



CCENOMYIID^ 



BB. Antennae consisting of not more than three segments; the third segment 



either with or without a style or an arista, but not divided into subsegments. 



C. Antennas consisting apparently of a single globular segment bearing a 



long, arista ; wings with some stout veins near the costal margin and other 



weaker veins extending across the wing unconnected by cross-veins 



(Fig. 1099). p. 847 Phorid^ 



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

 Figure 1099. p 847. 



D. Cells M and ist M2 not separated. (See Figures 1094 and 1095, p. 844 

 for examples of this type of wing- venation). 



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

 veins R2 -|- 3 and R4 -f 5; the cross-vein r-m at or near this swelling 



when present; frontal suttire absent, p. 843 Dolichopodid^ 



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

 veins R2 -t- 3 and R4 -f- 5; the cross-vein r-m more remote from the 

 base of the wing; the frontal sutiu-e present. (Muscoidea), Pass to 

 Table B. 

 DD. Cells M (or 2d M) and ist M2 separate. 

 E. Radial sector three-branched. 



P. Venation intricate due to an unusual anastomosing of the veins 



(Fig. 1077) p. 836 Nemestrinid^ 



FF. Venation not of the type represented by Figure 1077. 



G. Vertex of the head distinctly hollowed out between the eyes; 



eyes never contiguous, p. 840 AsiliDvE 



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

 often contiguous in males. 



H. Alulets very large, p. 837 Acrocerid^ 



HH. Alulets small or rudimentary. 



I. Cell Mj present. 



J. Vein Rs ending before the apex of the wing. p. 842.. 



APIOCERIDiE 



JJ. Vein R5 not ending before the apex of the wing. 



K. Empodia pulvilliform. p. 834 RHAGiONiDiE 



KK. Empodia wanting, p. 839 Therevid^ 



II. Cell M3 obliterated by the coalescence of veins M3 and Cui. 

 J. Third segment of the antennae without a style or an 



arista; vein Mi ending at or before the apex of the wing. 



p. 839 SCENOPINID^ 



JJ. Third segment of the antennae usually with a style or an 



arista; vein Mi ending beyond the apex of the wing. 



K. Vein Cua extending free to the margin of the wing or 



coalesced with vein 2d A for a short distance at the 



margin of the wing. p. 838 Bombylid^ 



KK. Vein Cxiz joining vein 2d A far from the margin of 

 the wing, often extending towards the base of the wing 



p. 845 Empidid^ 



EE. Radial sector with not more than two branches. 



F. Wings lanceolate and with no cross-veins except at the base. 



(Fig. 1097) p. 846 LONCHOPTERID^ 



FF. Wings not of the type represented by Figure 1097. 



G. Empodia pulvilliform. p. 837 , ACROCERID^ 



GG. Empodia not pulvilliform. 



H. Vein Cua not coalesced with vein 2d A to such an extent as to 

 cause the free part to appear like a cross-vein. 

 I. Antennae with a terminal style or arista. 



J. Antennae with a terminal arista, p. 848 . Platypezid^ 

 JJ. Antennae with a terminal style. 



