414 



UNITED STATES NATIONAL MUSEUM BULLETIN 224 



Genus Atoniomyia Hermann 



Figures 276, 276A-C, 672, 1333, 1342, 2047 



Atonia "VVilliston, Psyche, vol. 5, p. 257, 1889. Type of genus : 

 Atomosia mikii Williston, 1886. Designated by Williston, 

 1901. Preoccupied Coleoptera, 1848. 



Atoniomyia Hermann, Nova Acta Acad. Caes. Leop.-Carol., vol. 

 96, p. 81, 1912. Change of name. 



Quite small, robust flies with strongly punctulate 

 thorax and abdomen. The pile is short and appressed. 

 The terminalia are concealed and recessed, ocellarium 

 with 1 pair of bristles; the third antennal segment is 

 distinct in that it bears a stout, short, apical bristle 

 placed immediately above a moderately long, down- 

 turned microsegment. Tibial bristles extremely long. 

 Length 6 or 7 mm. 



Head, lateral aspect : The face is only visible in pro- 

 file on the lower half where it is moderately protuber- 

 ant and subrectangular; the eye is slightly recessed 

 below, strongly convex anteriorly; posteriorly it is 

 plane over the middle third, but distinctly convex above 

 and below. The occiput is rather tumid, especially to- 

 wards the medial plane but is completely obliterated 

 on the upper fourth. The occipital pile is moderately 

 long and fine and slightly more abundant below ; there 

 are 2 pairs of subdorsal, deeply medial, long, stout, 

 black, spinous bristles located on the occiput. Probos- 

 cis small, subcylindrical, the apex rounded off below ; 

 the base is distinctly swollen ; the apex bears an apical 

 and ventral fringe of pile, the basal half ventrally 

 with numerous, long, fine hairs, the dorsal ridge is 

 thin, transparent and low. The proboscis is directed 

 obliquely downward. Palpus composed of two minute 

 segments, the second especially small, the first sub- 

 globular and more or less fused at the base; it appears 

 to be not excavated and the second segment is attenu- 

 ate and not porate ; both segments bear a few, fine, long 

 hairs. Antenna attached to the upper third of the 

 head and moderately elongate; the first segment is 

 slightly swollen and as long or slightly longer than 

 the second, which is beadlike. The third segment is 

 narrow at the base, wider through the middle, and at 

 the apex slightly narrowed. The apex bears a stout, 

 short, bristly, apical spine dorsally and below it ven- 

 trally a moderately long, bluntly pointed microsegment. 

 First segment with 1 or 2 weak bristles and other setae 

 below and above, second with 2 moderately long, weak 



bristles ventrally. 



Head, anterior aspect: The face below the antenna 

 is a fourth the head width, with nearly parallel sides; 

 subepistomal region short, horizontal, plane and bare. 

 Face micropubescent with an irregular row of long, 

 fine pile sublaterally on each side, and with a sparse 

 cluster of bristles and stiff pile on the ventral third. 

 There are 4 bristles on each side in a vertical row 

 with pile between and laterally. There are also 3 pairs 

 of equally strong bristles directed downward from the 

 sides of the subepistomal margin. The front is rather 

 strondy divergent and pubescent, with a single row of 



6 or 7 long, slender bristles along the eye margin. Ver- 

 tex deeply excavated with slanting sides; the ocella- 

 rium is high and large, with nearly vertical sides; it 

 bears a single pair of long, stout, curved, divergent 

 bristles. 



Thorax : The mesonotum with pubescence only on the 

 humerus and in front of the scutellum. Pleuron pubes- 

 cent, with a bare stripe running down along the pos- 

 terior margin of the mesopleuron. Pile of mesonotum 

 abundant, golden, flat appressed, somewhat scalelike 

 and setate ; and among these setae are numerous, long, 

 fine, stiff suberect hairs which arise from punctures. 

 Humerus with 4 or 5 weak, bristly hairs; notopleuron 

 with 1 long, slender bristle, supraalar region with 1; 

 postalar region with 1 ; scutellum with 4 pairs of bris- 

 tles, its surface punctate with curled, flattened setae. 

 Acrostical and dorsocentral elements are not differ- 

 entiated. Pleuron with fine, scattered hairs, including 

 the pronotum ; anterior and upper portions of the meso- 

 pleuron with some scattered pile. Upper posterior 

 portion of mesopleuron with 1 to 3 distinct, long bris- 

 tles. Sternopleuron and posthypopleuron with a few 

 scattered hairs. Pteropleuron apilose; meta pleuron 

 with a vertical fanlike fringe of 10 to 12 especially long, 

 backwardly curved, slender bristles. Metanotal slopes 

 with 5 or 6 stout, spinous bristles in each of 2 patches, 

 a dorsal row immediately beneath the squama, also a 

 ventral lower patch. Metanotal slopes with abundant 

 long pile; metasternum with a few minute hairs; post- 

 metacoxal area chitinized, with seam; tegula pubes- 

 cent only ; squama with sparse fringe in several rows. 

 Prosternum not dissociated. 



Legs: The femora are relatively slender; the hind 

 femur is very slightly thickened before the apex. This 

 femur bears short, appressed pile dorsally, a subapical 

 and apical pair of weak, bristly hairs dorsally, with a 

 third pair at the outer fifth; there are a few, long, 

 slender hairs laterally and a ventral fringe of 3 quite 

 long, slender hairs and 4 other shorter hairs in addition 

 to the short, scanty, ventral fringe. This tibia bears 

 very slender bristles or bristly hairs as follows : 5 or 6 

 dorsal ; 2 exceptionally long, stout, apically fine dorso- 

 lateral; 1 additional element laterally and basally, and 

 3 or 4 long, slender, curved ventral bristles. Ventrally 

 this tibia has a characteristically dense, erect, rather 

 long fringe ; apical bristles slender and reduced. Mid- 

 dle femur with a single anterior bristle at the apical 

 fourth and a posteroventral fringe of scattered long 

 hairs; its tibia bears anteriorly a slender, basal bristle, 

 2 pairs of excessively long, basally stout, apically fine, 

 oblique bristles. These bristles are three-fourths as 

 long as the entire tibia : it also bears dorsally 5 or 6 fine, 

 shorter bristles, and posteroventrally 3 excessively long 

 bristles. Ventral fringe short and suberect. Anterior 

 femur with fringe of 7 or 8 long hairs ventrally and a 

 few long hairs posteriorly; anterior tibia with 5 or 6 

 slender, short dorsal, 4 or 5 long, posterior, a like num- 

 ber of long posteroventral and 3 or 4 long, ventral 

 bristles increasing in length apically. Apical circlet 

 with 12 bristles. On both the middle and anterior tarsi 



