68 R. W. CROSSKEY 



pairs of strong setae, the bend of vein M lacks an appendage, cell R 5 is open to 

 the wing margin or only just closed, and there are two or three stpl setae. Some 

 forms occur, less typical of their tribe, that have hairy eyes, four post dc setae, 

 infrasquamal hairs, and three pairs of scutellar setae. Pallid coloration and reddish 

 yellow legs are rather commonly found in the group, and there is a tendency for 

 the tibiae of the males of the really long-legged forms to become extremely slender 

 and sinuous with associated reduction of the bristling (here it should be noted that 

 the mid tibia in Leskiini appears always to possess a submedian v seta but that this 

 is often extemely small in long-legged males). 



The endemic genus Exechopalpus possesses extraordinarily long palpi, similar to 

 those of the Neotropical genus Spathipalpus Rondani, and the proboscis itself is 

 extremely slender. Throughout the Leskiini there is a marked tendency for the 

 proboscis to be unusually slender, elongate, almost stylet-like, with the labellae 

 correspondingly reduced, and even in forms in which the proboscis is short it is 

 usually found that the mentum is parallel-sided in profile rather than convex 

 on its lower edge. 



The genus Bezziomyiobia Baranov from the Solomon Islands has not been 

 found in Australia, but is included in the following key to genera to show its main 

 features. It is extremely close to Demoticoides Mesnil, and the latter ought perhaps 

 to be sunk as a synonym of Bezziomyiobia (it is beyond the scope of the present work 

 to consider this further). 



Key to Australian Genera of Leskiini 



i Scutellum with only two pairs of strong marginal setae, the basals and subapicals; 

 apical scutellar setae minute and hair-like or absent, if weakly developed then 

 directed half-upwards. Subapical scutellar setae not inserted very widely apart, 

 distance between their bases subequal to or less than that between a subapical 

 seta and its corresponding basal seta ........ 2 



— Scutellum with three pairs of strong marginal setae, a pair of strong horizontal 



crossed apical setae present in addition to the basals and subapicals. Subapical 

 scutellar setae inserted very widely apart, distance between their bases about twice 

 as great as that between a subapical seta and its corresponding basal seta (or even 

 more than this) ............ 8 



2 Palpi exceptionally elongate, length about equal to that of head at level of the 



epistome; palpi projecting beyond epistome by a distance about equal to the 

 antennal length (when proboscis retracted). Fore tibia with some strong ad 

 setae. Mid tibia with three or four strong ad setae and with three strong p 

 setae. Hind tibia with a pv apical seta . . . EXECHOPALPUS Macquart 



- Palpi normal, length conspicuously less than that of head at level of the epistome; 



palpi not or only a little projecting beyond epistome (when proboscis retracted) 

 (Text-fig. 41). Fore tibia without ad setae (a few inconspicuous ad setulae on 

 basal half in Rhinomyobia) . Mid tibia with one or two ad setae and nearly 

 always with two p setae (some Toxocnemis-like forms with a very small third p 

 seta basad of the normal two). Hind tibia without a pv apical seta (except in 

 Sipholeskia) ............. 3 



3 Abdomen with Ti + 2 excavate to its hind margin. Second costal sector bare 



ventrally. Humeral callus with three or more setae in line (sometimes not 

 clearly differentiated from long hair). More robust forms with subovate or 

 subconical abdomen ........... 4 



