FAM, EMPIDIDJE 49 
SusBFAMILY OCYDROMIINZE 
Characters. — Small, delicate species, usually with shining body and yellow legs, bristles 
never strongly developed: thorax rarely very gibbous, shorter than the narrow cylindrical abdomen. 
Head more or less globular, rarely somewhat hemispherical; eyes never hairy, of the males broadly 
contiguous on the front (except in Lejtometopiella), the facets of the upper two-thirds usually large, 
sometimes the eyes are contiguous in the females also (e. g. Leftopeza, etc.) in which case they meet on 
the face as well; antenne often elongate due to a tendency toward enlargement of the third joint, the 
first joint usually abortive or fused with the second, sometimes (QZdaiea) the third joint is remarkably 
lengthened, sometimes (An?halia) this joint is broadly orbicular; the antennz terminate in a long bare 
filiform arista, subdorsal in Ocydromia, or in a short, thickened two-jointed style, the latter rarely may 
be entirely absent; proboscis usually very short, scarcely protruding, sometimes as long as the head and 
more or less porrect; palpi small, single-jointed, usually narrowly cylindrical and with a few setze, 
rarely the palpi are dilated; ocellar tubercle prominent in the male and then located on the very summit 
of the head, in dichoptic females the ocelli are not raised and are placed in front of the vertex ; ocellar, 
vertical and occipital bristles never strongly developed although present. Thorax without discal 
bristles, the lateral bristles comprising a few notopleural, humeral, postalar and prescutellar bristles, 
several marginal but no discal bristles to the scutellum ; pleure always devoid of bristles, but in Le$- 
lopeza, etc., somewhat villose in front of the metathoracic spiracle. Abdomen of the male with loose 
long fine hairs, pygidium small to minute, symmetrical, closed, the lateral valves largest, the dorsal valves 
reduced; represented by filament-like appéndages, penis short and thick ; an ovipositor usually developed 
from the last three or four segments. Legs typically slender and simple, sometimes (Qdalea, Scelolabes) 
there is a tendency for the hind legs to become raptorial similar to the parallel development in the 
Hybotinz; coxe never lengthened, tibizee without bristles, except in Lejtofeza and Hoflopeza, tarsi 
normal, pulvilli small, empodium microscopic. Calypteres very small but with a well developed fringe. 
Wings large, anal angle prominent and rectangular, except in Leptometopiella, no alula, costa evanescent 
beyond the fourth vein, the hind margin of the wing never thickened, basal bristle of costa usually 
present, marginal hairs weak, no setule; auxiliary vein rather weak, straight, parallel with and close to 
the first vein, evanescent before its end, first vein ending between three-fifths and three-fourth the 
wing-length, pedicel of the second and third vein arising over the basal half of the second basal cell, 
except in S/enofroctus, third vein always simple, discal cell large, located near the middle of the wing, 
complete or rarely opening into the third posterior cell, intercalary vein present except in S/enoProctus 
and Scelolabes, sometimes the fourth vein is lacking beyond the discal cell (Leftopesa, etc.) in which case 
the intercalary vein functions as the fourth vein; basal cells subequal in length, of moderate size, never 
very short or very long, the second basal sometimes broader than the first; anal cell shorter than the 
basals, truncate apically, the anal crossvein reflexed, nearly straight and abruptly meeting the anal vein, 
the latter always faint but often attaining the wing-margin. 
This group is an offshoot of the Hybotinaz. [tis quite probable that some ancestral form in 
the Ocydromiinz was responsible for the Tachydromiinz, and that of the modern genera Trichina, 
or better still, A/authalia £allida, is structurally nearest to that form. 
SYNOPSIS OF THE GENERA OF THE OCYDROMIINZE 
A. Discal cell emitting three. simple posterior veius, rarely the discal cell 
open in which case the intercalary vein is joined to the fourth, first 
vein ending near three-fifths the wing-length, stigma usually dis- 
