1154 
DIPTERA OF AUSTRALIA, 
title Platyura, but judging from the note appended to liis descrip- 
tion the insect is evidently not Platyura. The four genera 
named by Loew, from fossil specimens discovered in amber, it 
appears are extinct. 
Imayo. 
External structure. 
The head is narrower than the thorax, round or oblong, flattened 
or flattened-hemisphei’ical on the fore part, situated deep in the 
thorax. Front of both sexes broad. Eyes round or oval, fre- 
({uently emarginate on the inner s’de or reniform, set with short 
hair. Ocelli three or only two ; in the former case they are either 
disposed in a triangle, in a bent or sometimes a straiglit line on 
in the front, or two are situated, one at the inner border of each of 
tlie compound eyes, and the third placed in the middle of the 
anterior border of the front ; in the other case always at the inner 
border of the compound eyes. Proboscis short, retired, rarely 
elongated or beak-.shaped. Palpi three- or four-jointed, prominent, 
generally incurved ; the first joint always very small. Antennae 
generally arcuated, projecting forwards, straiglit or diverging 
sidewards, 2--I-10- to 2--f- 15-jointed ; the joints of the scapus 
distinctly set-off’, first one cylindrical or cyathiform, rarely ciipuli- 
form, second joint cupuliform or cyathiform, both usually setiferous 
at the apex ; flagellar joints cylindrical, compressed-cylindrical, 
orbicular, or setiform, with a downy pubescence, .seldom verti- 
cillate-setose. Thorax ovate, more or less arched ; prothorax with 
short, close pubescence, sometimes with longer hair, frequently this 
is mingled with setiferous hair ; latei’al and posterior borders 
setiferous ; metathorax highly arched or perpendicular ; scutellum 
generally small, semi-circular, sometimes large, rounded-triangular, 
generally setiferous ; no transver.se suture. Halteres naked or 
with a minute pubescence. Abdomen six- or seven-segmented, 
rarely eight-segmented ; cylindrical or compressed from the sides, 
narrower at the base ; ^ with a large or small anal joint 
and holding forceps ; $ with an ovipositor provided with two 
terminal lamellae ; the hair, except in a few cases, short and lying 
