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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



pubescence and a patch of pubescence beneath the an- 

 tenna. Middle of the face also pale pubescent but ap- 

 pearing dark, except in an oblique light. Epistoina 

 quite small, short and not quite horizontal. The front is 

 short, narrow, micropubescent but without bristles; 

 such as is present is very minute; there is a distinct, 

 deep fossa on each side. The ocellar protuberance is 

 cylindrical, with 2 rather long, slender, browning black 

 bristles, divergent and curved backward. 



Thorax : The mesonotum is polished, shining, black, 

 apparently without acrostical elements and with a 

 single row of distinct, fine, scattered, scanty, suberect, 

 dorsocentral hairs. Bristles are present as follows: 1 

 notopleural, 1 supraalar quite long and rather slender, 

 1 postalar shorter and still more slender, and 1 pair of 

 quite long, rather stout, closely adjacent, brownish 

 black scutellar bristles directed obliquely upward. 

 Pleural bristles are confined to the metapleuron, where 

 there are 4 quite long, slender, fanlike, yellowish bristles 

 turned downward apically and 3 or 4 other shorter, fine 

 hairs. Postmesopleuron with 1 or 2 hairs; there are no 

 bristles, but 1 or 2 scars present suggest that there may 

 have been weak bristles. Hypopleuron with 2 or 3 long, 

 fine hairs; metanotal slope with 2 or 3 fine, slender, 

 bristly hairs, pale in color. Sides of metasternum pilose 

 with numerous, fine hairs; postmetacoxal ai'ea heavily 

 chitinized and longer than wide. 



Legs: The hind femur is slightly lengthened and 

 rather distinctly thickened; it bears short, scanty, ap- 

 pressed pile ; the ventromedial margin has a long, dense 

 fringe of fine, erect yellowish, unmodified hairs from 

 near the base to near apex and it bears rather long, 

 slender bristles consisting of 3 laterally at the middle 

 and beyond, 1 dorsally at the apex and 1 medially near 

 the apex, and 3 very slender and long anteroventral, be- 

 sides 2 or 3 quite long, slender ventromedial hairs. 

 Hind tibia with matching ventral fringe becoming an 

 almost scalelike mat at the apical eighth and rather 

 more prominent, quite long bristles. There are 2 lateral 

 and 4 dorsal, the last 2 quite long. Middle femur 

 slightly thickened on the outer third and rather slender 

 on the whole, with a weak, long, anterodorsal bristle on 

 the outer third, 3 ventrally, the outer two are quite long ; 

 middle tibia quite slender with extremely long, oblique 

 bristles, 4 ventral, 2 lateral, and a few other long hairs 

 and short, subappressed, ventral pile. The anterior bris- 

 tles of the middle basitarsus as long as two tarsal seg- 

 ments. Anterior femur with 2 or 3 quite long, slender, 

 bristly hairs ventrally; this tibia has 4 moderately long, 

 dorsal and 3 still longer oblique anterior and 3 posterior 

 ventral bristles. First segment of the tarsi with extraor- 

 dinarily long, anteroventral, anterodorsal apical bris- 

 tles and posterobasal bristle; other bristles shorter. 

 Claws rather short, sharp; pulvilli nearly as long as 

 claws; empodium as long as pulvillus, basally stout. 



Wings : There are only 4 posterior cells present ; one 

 completely missing, which appears to be the third pos- 

 terior cell; all other posterior cells open maximally. 

 Anal cell closed with a short stalk; marginal cell closed 

 with a short stalk; the discal cell ends with 1 straight, 



transverse vein, second basal cell closed with 3 veins, 

 the middle vein short. Ambient vein ends in the middle 

 of the anal cell ; alula quite narrow. 



Abdomen : The abdomen is slender and subcylindrical 

 though slightly flattened on the first two or three ter- 

 gites ; it is strongly punctulate and is very slightly but 

 gradually widened; the base is nearly as wide as the 

 mesonotum. Sides of first tergite with 4 rather stout, 

 white bristles in a vertical row; middle of the sides of 

 the second to fourth tergites each with a rather long, 

 distinct, slender, white bristle. There are 7 tergites 

 present in the male. Abdomen thin, the sides moder- 

 ately rolled. Male termmalia small, inconspicuous, 

 completely hidden by the incompletely cupped over 

 abdomen. 



Distribution: Australian: Opocapsis dioctroides 

 Walker (1860). 



Genus Atomosiella Wilcox 



Figures 220, 671, 1334, 1343 



Atomosiella Wilcox, Pan-Pacific Ent., vol. 3, p. 40, 1937. Type 

 of genus : Atomosia antennata Banks, 1920, by original 

 designation. 



Small, short, scantily pilose flies with strongly punc- 

 tulate abdomen and the general appearance of Atomosia 

 Macquart. Like Atomosia they carry a minute spine 

 near the middle of the third antennal segment; it is 

 somewhat more inconspicuous and difficult to discover 

 as it is subdorsal and lateral in position. These flies are 

 immediately recognized by the presence of only 4 pos- 

 terior cells; the third is wanting. Probably related to 

 Cerotainia Schiner. Length 7 or 8 mm. 



Head, lateral aspect: The face is scarcely visible in 

 profile, except for a small, low triangle below which is 

 due to the recession of the eye. The eye is strongly con- 

 vex anteriorly, gently and evenly convex posteriorly. 

 Occiput narrow, but evenly developed except at the im- 

 mediate vertex, where it is wanting. The occipital pile 

 is very scanty and consists of a few, fine, bristly hairs 

 below and some fine pile at the extreme base and 8 pairs 

 of bristles on the upper half; the bristles behind the 

 vertex are more prominent. The proboscis is quite 

 small, short, very obtuse apically and somewhat con- 

 stricted below in the middle, giving the base a swollen 

 appearance. It is a little constricted laterally, has 

 abundant, short, fine pile at the apex, and some long 

 hairs ventrally below; the proboscis is thrust chiefly 

 forward and is not longer than the face. Palpus minute, 

 composed of 1 segment, short, obtuse, attached to a 

 curved, concave ledge next to base of proboscis ; it has 

 6 or 7 fine, long hairs. Antenna attached at the upper 

 third, the first segment is more than twice as long as the 

 second and the second segment is beadlike. The third 

 segment is slender and nearly twice as long as the com- 

 bined length of the first two ; it is rather flattened with 

 blunt apex and carries beyond the middle subdorsally 

 and laterally a small yellowish spine located in an in- 

 conspicuous pit. First segment with a single, rather 





