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 g 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 4; 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 vo? 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 za setae in most forms, sometimes 0 + I ia; 2(3) + 3(4) dc setae; acr 
setae reduced, usually 0 + 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; infrasquamal 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 R; 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,, ; that 
reach part way to, or fully as far as, yv-m; last section of Cu, as long as m—cu; distance on 
vein M from bend to m-—cu usually as long as or longer than distance from v—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; T1 + 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. 
KeEy To AUSTRALIAN GENERA OF PALPOSTOMATINI 
I Prosternum bare. No definite vibrissae or vibrissal angle. One post ta seta. 
[Oriental Region including Japan] . - c . EUTRIXOPSIS Townsend 
— Prosternum with one or more long seta or Safe on each side directed downwards. 
Vibrissae distinctly developed and head with definite vibrissal angle. Two 
post ia setae. [Australia] é 5 ; : : ¢ : . 6 3 2 
2 Propleuron bare 
