42 R. W. CROSSKEY 



absent (present at least in some species of Chetogaster) ; scutellum typically with three pairs 

 of strong marginal setae (Text-fig. 70) (including crossed or convergent apicals) but most 

 Rutiliini with more pairs of marginals (4-1 1) and apicals often reduced; mid tibia with a v 

 submedian seta; hind tibia with or without pv apical seta; suprasquamal ridge often haired 

 (Rutiliini) ; abdominal Ti + 2 usually excavate to its hind margin (not in Doleschallini) ; 

 abdominal sternites concealed by ventral ends of tergites meeting in mid line, at most only 

 slightly exposed and tergite venters slightly parted; <J aedeagus long and slender and armed 

 with a backwardly directed spinus (epiphallus) at junctions of the basiphallus and distiphallus 

 (Text -fig. 22). 



The curious small tribe Doleschallini, which occurs in the Oriental Region 

 eastwards to New Guinea and the Solomon Islands, has not been found in Australia. 

 It seems just possible, however, that it might be represented in northern Queensland, 

 and the tribe is therefore included in the following key to tribes. The Doleschallini 

 includes the most slender elongate forms found in the Tachinidae and the adults 

 are noteworthy for their habit of resting motionless (and well disguised) on the 

 trunks of trees (especially coconut and, in New Guinea, Casnarina) with their 

 exceedingly long spindly legs outstretched. 



Key to Australian Tribes of PROSENINAE 



[Note : Doleschallini is included although the tribe is not yet known from Australia.] 



1 Abdominal Ti + 2 excavate to its hind margin. Thorax membranous medially 



or mainly so between bases of hind coxae and abdominal insertion, coxae and 

 abdomen not unusually remote from each other. Head in profile not strongly 

 subtriangular, as long at the epistome (or nearly as long) as at the level of the 

 antennal axis. Head often with a strong facial carina. Notopleuron distinctly 

 differentiated from the scutum by a groove or shallow depression. Body form 

 usually robust, but if long and slender then abdomen broadest near base or 

 subfusiform ............. 2 



- Abdominal Ti -f- 2 excavate only at the base. Thorax closed above the hind coxae 



by a broad sclerotized bridge (as in Cylindromyiini) , the hind coxae widely 

 separated from the abdominal base. Head in profile subtriangular, profrons 

 extraordinarily prominent and lower part of head strongly receding, head very 

 much longer at antennal axis than at level of the epistome. Head without facial 

 carina. Notopleuron not differentiated from the scutum by any depression. 

 Body and legs excessively long and slender, the abdomen with subparallel sides 

 (i.e. not distinctly fusiform or widest at base) .... DOLESCHALLINI 



2 Postalar callus with only the normal two postalar setae (at most only a weak setula 



in addition). Suprasquamal ridge and postalar wall bare. Epistome not 

 produced in front of vibrissal insertions (Text-figs 29-30) or only slightly so 

 (Text-fig. 27), usually not much visible in profile. Propleuron bare or haired. 

 Barette bare or sparsely haired anteriorly (if all haired then no facial carina). 

 Facial carina present or absent. Scutellum with three pairs of marginal setae 

 (some supernumerary marginals differentiated in Rutilotrixa). Male hypopygium 

 without long strong erect setae on T7 -f- 8 (except in Acucera). Prosternal 

 membrane and presternum totally bare ..... PROSENINI (p. 43) 



- Postalar callus with supernumerary strong setae, with a total of 3-6 setae (except 



in Chetogaster). Either suprasquamal ridge or postalar wall usually haired. 

 Epistome subnasute or at least slightly and distinctly projecting in front of the 

 vibrissal insertions in profile (Text-fig. 31). Propleuron haired. Barette thickly 



