54 R. W. CROSSKEY 



Hamaxioides Mesnil has not been seen but appears from description to be a true 

 palpostomatine distinct from Palpostoma: it differs most notably by having the 

 prosternum bare.) 



The principal features of the Palpostomatini are as follows. Eyes bare, in <J usually very 

 strongly approximated above and with the uppermost facets conspicuously larger than the 

 lowermost facets ; ocelli present, often on a very strongly raised ocellar tubercle (Text-fig. 39) ; 

 inner vertical setae crossed, sometimes virtually absent in g; proclinate orbital setae very 

 weak and even sometimes absent in females as well as males; face very deeply excavate and 

 strongly warped forwards at the epistome, but epistome not visible in profile; vibrissae weak 

 or sometimes virtually absent, level with or a little above epistomal margin, lower ends of 

 facial ridges often with some characteristic small stubby setulae adjacent to the vibrissae; 

 parafacials sparsely short haired; genal dilation weak or absent; facial ridges bare (excepting 

 the black setulae adjacent to vibrissae); occiput usually rather sunken; frontal setae weak 

 or almost hair-like, rows extending down to about the level of the first antennal segment; 

 arista pubescent; proboscis short, labellae usually with a posterior palpiform process (whence 

 the name Palpostoma); palpi well developed; prosternum usually with one or two very long 

 downwardly directed setae or strong hairs on each side, sometimes bare; prosternal membrane 

 bare; propleuron bare or haired; two strong humeral setae, sometimes minute third seta 

 distinguishable; o + 2 ia setae in most forms, sometimes o + 1 ta; 2(3) + 3(4) dc setae; acr 

 setae reduced, usually o + 1 or 1 + 1 but variations occur; pre-alar seta absent (or at most 

 minute and hair-like) ; one sa seta only (this very strong and conspicuously isolated in the 

 absence of a pra or a second sa seta) ; 2 or 3 stpl setae ; barette bare ; pteropleural seta absent 

 or weak; scutellum usually with only two pairs of marginal setae (basals, and convergent 

 or crossed apicals) and without discal setae (third, lateral, pair of scutellar setae present in 

 Eutrixopsis) ; postscutellum weakly developed, sometimes almost absent ; inf rasquamal hairs 

 present or absent; fore coxa bare on inner anterior part; leg setae rather reduced, mid tibia 

 without or with a very small submedian v seta and with one small ad seta; hind coxa not 

 very remote from abdominal base, bare posterodorsally; hind tibia with two dorsal preapical 

 setae and without pv apical seta; tarsi not flattened; second costal sector haired ventrally; 

 cell i? 5 open or short petiolate or closed at the wing margin; bend of vein M rounded or 

 moderately sharp and appendiculate ; veins bare above except for fine hairs on R i+b that 

 reach part way to, or fully as far as, r-m; last section of Cu l as long as m-cu; distance on 

 vein M from bend to m-cu usually as long as or longer than distance from r-m to m-cu; 

 lower calypter very strongly diverging from scutellum, evenly rounded on its hind margin; 

 abdomen with weak bristling and Ti + 2 not excavate to its hind margin; Ti + 2 without 

 median marginal setae; sternites concealed. 



The Australian fauna includes two genera in addition to Palpostoma, viz. 

 Apalpostoma and Eustacomyia; these are very little known genera, not recorded 

 since the original descriptions of their included species, but are here accepted as 

 valid genera distinct from Palpostoma. The Oriental genus Eutrixopsis is included 

 in the following key, although as already pointed out there is some doubt as to 

 whether it truly belongs in the Palpostomatini. 



Key to Australian Genera of PALPOSTOMATINI 



1 Prosternum bare. No definite vibrissae or vibrissal angle. One post ia seta. 



[Oriental Region including Japan] ..... EUTRIXOPSIS Townsend 

 - Prosternum with one or more long seta or hair on each side directed downwards. 

 Vibrissae distinctly developed and head with definite vibrissal angle. Two 

 post ia setae. [Australia] .......... 2 



2 Propleuron bare ............ 3 



