DIPTERA 
Anal angle of the wing almost always more or less projecting, often rectan- 
gular, rarely the wings uniformly tapering io the base, im which case 
the high mesopleure or thin hind margin of the wing are distinctive, a 
transverse fold im the wing membrane between the origin of the fourth 
vein and the humeral crossvein; males often holoptic; Proboscis usually 
rigid; mesopleure distinctly higher. than lomg; front coxe mot elongate 
nor ihe front legs raptorial, empodium at most microscopically setuliform, 
usually invisible; flying species .. . . $ ned 
3. Front legs raplorial, located near the head amd distant « Ji e Mteisc 
pairs, the front coxe greatly lengthened, nearly as long as their femora 
and two or more times as long as the posterior coxa, the front femora more 
or less thichened and selulose and selose beneath; palpi minute ; antenne 
inserted below the middle of the head ; body and legs often yellow; neuration 
oflen reduced, pedicel of the second and third veins arising mearer the 
anterior crossvein than to the humeral crossveinm . . . AC 
Legs slender, not raptorial, the front pair not distant from the si the 
mesosteruum never greatly longer than the prosternum, neither. the front 
coxe greatly lengthened mor the. front. femora. greatly thichened; antenna. 
usually above the middle of the head; body often olivaceous black, thorax 
flattened. before. scutellum;  meuration. complete, edicel of the second and 
ihird veins arising nearer. the. humeral  crossvein. than to the anterior 
crossvein, auxiliary vein always distinct... . 5... . . ,. V 
4. Anal crossvein recurved or abruptly reflexed and. confluent. with the under side 
of the anal cell, the anal vein usually represented as an independent fold 
disjoined from the anal cell, the crossvein perpendicular only in Paratha- 
lassius, auxiliary vein strong and always distinct from the firsl vein, third 
vein forked or not, if not the melapleura setose or the basal cells very small 
or the anal cell very narrow, always three posterior veins, basal cells long 
and coexteusive, except iu the Microphorus group ; antenne obviously three- 
jointed, except in. Hormopeza, the basal joints often more or less setose, 
the first. joint rarely. shorter than the second; proboscis often elongate, 
usually bent bach, varely projecting, palpi often long and. hairy, especially 
loward ihe base; eyes of the female always broadly separated, fronto- 
orbitals often present; face quadrate or arched, almost never very narrow; 
metapleure often with bristles ; posthumerals and intra-alars usually present, 
unless all the bristles are secondarily reduced ; no ovipositor, the female with 
two styles; middle tibie usually with an afical bristle inside, hind tibia 
often with extensor bristles. .. ..— c£: s eo NIRE 
Anal crossvein. forming a. distinct angle, viter Mid right or slightly obtuse, 
toith the under side of the anal cell. which is continuous with the anal vein, 
recurved only in Anomalempis, third vein. forked only in some Brachy- 
stomatinze, oflem only two posterior veins; base of the antenna without 
strong sele; proboscis rarely longer than the length of the head, often 
porrect, palpi short, at. most. with a few sete toward the tip; face often 
narrow; no fronto-orbital or intra-alar. bristles, fosthumerals present. only 
in Trichina and Bicellaria; thorax often large and highly arched, meta- 
Subfam. HH aieichopE QNO 
Subfam. CLINOCERATIN.E. 
Subfam. ExripiN A. 
