12 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



7 ' Vf/r'Tm 



The asilid abdomen typically has eight well developed 

 tergites in the males and females, those beyond being 

 incorporated within the terminalia or the ovipositor. 

 In the female Asilinae, if the proctiger be counted, ten 

 segments can be discovered, but in other subfamilies 

 sometimes fewer. In one tribe and subfamily the pre- 

 abdomen is reduced to six visible segments. Macro- 

 chaetae, with few exceptions, are present on the sides 

 of the first tergite. They are more rarely present on 

 remaining tergites, still more uncommonly on sternites. 

 In a few asilids the abdomen departs from the usual 

 stout and tapered, cylindroid form to become wide and 

 greatly flattened (Blepharotes West wood) or wide and 

 stout and robust {Hyperechia Schiner, Laphria Mei- 

 gen). Rarely are asilids petiolate. A few have long, 

 very slender bodies, as in the sluggish Leptogastrinae. 

 The first sternite may be subdivided into two or more 

 bands of thin chitin. 



In the Asilidae the male terminalia are complex and, 

 as is true of so many Diptera, quite variable. Since 

 there is still much confusion of terms in dealing with 

 these structures, I shall define below the terms I have 

 adopted in this work. I have consulted both Crampton 

 (1942) and Cole (1927), but I have relied chiefly on 

 the terminology employed by Emden and Hennig 

 (1956). 



The genitalia of the asilids and Diptera in general 



Text-Figure 4. — a-b, Bombomima fuhithorax Fabricius: a, deep 

 dissection with right clasper and pseudoclasper removed; B, 

 with gonopod removed, c, Nerax interruptus Macquart, with 

 superior forceps and gonopod removed. D, Neoaratus sp., 

 with superior forceps removed, revealing paralobus and clasper. 



comprise the ninth abdominal segment with marked 

 modifications in consequence of its function. The ter- 

 gal component is referred to as the epandrium, except 

 where it is furcate, in which case it is here styled the 

 superior forceps; this structure bears the proctiger at 

 its apex medially, a structure called by some authors 

 the lamellae and called by others the cerci, with due 

 recognition, perhaps, to the eleventh segment origin of 

 the true cerci. The proctiger, as found in the Asilidae, 

 may possibly represent parts of both tenth and elev- 

 enth segment (telson) elements; partly paired as it 

 often is by reason of a dorsal, lineal fissure, it repre- 

 sents a small, tubular passageway. 



On the ninth segment, the ventral or sternal element 

 or hypandrium, is usually present and is often extraor- 

 dinarily prominent; however, it is greatly reduced in 

 some genera and may be virtually or completely lack- 

 ing, as in Clephydroneura Becker; on the other hand it 

 is extended dorsally in Bathypogon Loew and even 

 fused to the epandrial element, from which the supe- 



