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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



Neotropical: Taracticus acioulatus Pritchard 

 (1938) ; argentifacies James (1953) ; guerrerensis Prit- 

 chard (1938) ; nigrimystaceus Williston (1901) ; 

 nigripes Williston (1901) ; similis Williston (1901) ; 

 vitripennis Bellardi (1861). 



Genus Paralaracticus Cole 



Fiodees S3, 516, 985, 994, 1743, 1871, 1952, 2028 



Parataracticus Cole, Pan-Pacific Ent, vol. 1, p. 11, 1924. Type 

 of genus: Parataracticus rubidus Cole, 1924, by original 

 designation. 



Quite small flies, easily recognized by the absent or 

 reduced pulvilli, of which there are at most minute 

 stubs, combined with the long, somewhat bladelike third 

 antennal segment which carries a bristly subapical 

 spine. The face is short, with very coarse bristles, 

 and all the marginal cells of the wing are open. Each 

 tergite bears very stout, short bristles laterally. Length 

 5 to 7 mm. 



Head, lateral aspect : The head is of medium length, 

 face quite short, a little more prominent below due 

 to the recession of the eye. Occiput prominent in the 

 middle and still more below, the posteroventral reces- 

 sion of the eye beginning a little below the middle 

 of the head. The pile is scanty but long and fine 

 ventrally. Stout bristles begin at or below the middle 

 of the head and consist of 8 pairs besides 4 behind 

 the vertex. The proboscis is short, stout, cylindrical, 

 laterally compressed toward the apex and slightly 

 truncate dorsally towards the apex. Palpus minute; 

 the first segment is extremely small and more or less 

 fused medially; the second segment is long, slender 

 and cylindrical. The antenna is attached a little 

 above the middle of the head; the first two segments 

 quite short, especially the second; only the first seg- 

 ment bears bristles or pile ventrally, and it has 2 or 

 3 stout bristles. Third segment more or less flattened, 

 beginning to increase in width from near the base, and 

 beyond the middle very slightly decreasing in width. 

 The apex is blunt and located dorsally a considerable 

 distance from the apex; there is a shallow incision 

 with a bristly spine. The third segment is 5 or 6 

 times the combined length of the first two segments. 

 The whole antenna is a little longer than the head. 



Head, anterior aspect : The head is moderately wide 

 and wider than the thorax. The face is quite wide, 

 with parallel sides, pubescent, without pile or at most 

 a few short hairs; however, the face does have nu- 

 merous, quite stout, yellowish bristles. The front is 

 slightly divergent, with 3 stout bristles near the eye 

 margin; vertex moderately excavated, the ocellarium 

 large with slanting sides and bearing 1 pair of stout, 

 long, postocellar bristles and sometimes a shorter pair. 

 Anterior eye facets a little enlarged. 



Thorax : The thorax is moderately hump-backed and 

 convex; the pile scanty, fine and setate. Acrostical pile 



or bristles absent ; dorsocentral bristles strongly devel- 

 oped anteriorly as well as posteriorly. The lateral 

 complement of stout bristles consists of 4 humeral, 1 

 posthumeral, 2 notopleural, 1 supraalar, 1 long and 2 

 minute postalar, and 3 to 5 pairs of scutellar. Scutel- 

 lum flat, without pile. Pronotal collar and cervical 

 sclerite with only fine pile. Lateral pronotum with 

 4 stout bristles. Metapleuron with a vertical row of 

 6 to 8 long, slender bristles. Remainder of pleuron 

 apilose and partly nonpollinose. Metanotum micro- 

 pubescent only. Metastemum laterally and ventrally 

 with fine pile. Postmetacoxal area membranous. Pro- 

 sternum dissociated. 



Legs : The femora and tibiae are stout but not swollen, 

 the former with appressed, short, setate pile. Hind 

 femur with a few conspicuous bristles : 1 lateral on the 

 basal half, 1 distal, 2 dorsolateral near the apex, the 

 same number of dorsomedial, and 1 or 2 small apical 

 lateral bristles. Middle femur with 1 bristle posteri- 

 orly at the apex and 3 small bristles anteriorly at the 

 apex. Bristles of tibia and tarsus well developed. 

 Hind tibia with 4 dorsal, 5 lateral and sometimes 3 or 

 4 additional bristles near the base, and 6 ventrolateral 

 bristles. Middle tibia with 6 dorsal, 5 or 6 longer an- 

 terodorsal, 10 posterior, and 4 long posteroventral 

 bristles. Anterior tibia similar with a partly doubled 

 anterodorsal row of bristles in addition to a dorsal row. 

 They have 8 posterior and 3 posteroventral bristles. 

 Apex of protibia with no process, but with a fine, 

 twisted, black spine. Basitarsus unmodified. Pulvilli 

 apparently absent and reduced to a spot of minute fuzzy 

 pile at the base of the claw. Empodium half of the 

 length of the sharp, gently curved and apposed claws. 



Wings : The wings are broad, the marginal and all of 

 the posterior cells and the anal cell widely open. Alula 

 of moderate length; ambient vein complete; wings 

 immaculate. 



Abdomen : The abdomen is comparatively broad and 

 robust; at the base it is fully as wide as the thorax, 

 slightly or sometimes strongly tapered. Pile quite 

 scanty and scattered, fine and appressed including the 

 margins. The sides of the first tergite have 4 to 6 

 stout spines; remaining tergites without spines in the 

 female but with 3 or 4 stout spines in each posterior 

 corner in the male. Abdomen more or less shining, 

 with small pairs of transverse pale pollinose spots. 

 Male with six well developed tergites, the seventh to- 

 tally concealed. Females with eight tergites, progres- 

 sively and slightly reduced in length beyond the fourth. 

 Male terminalia small, short and inconspicuous, the 

 epandrium with a triangular cleft almost or possibly 

 reaching quite to the base. Gonopod small and of 

 about the same length. Hypandrium short; genital 

 cavity exposed. Females with 6 pairs of slender, sharp, 

 attenuate spines upon the acanthophorites. 



Distribution : Nearctic : Parataracticus niger Martin 

 (1955) : rulidus Cole (1924) ; wyliei Martin (1955). 



