448 ENTOMOLOGICAL NEWS [Dec., '13 



ments dark brown, the flagellar segments much paler, whitish ; front, 

 vertex and occiput light greyish brown, darker behind. 



Mesonotal praescutum light brown, unmarked ; scutum, scutellum and 

 postnotum of about the same color, the latter a little darker. Pleurae 

 uniformly brown. Halteres brown, the base of the stem paler. 



Legs, coxae and trochanters dull yellow, femora almost white with 

 the tip broadly dark brown, tibiae whitish with the tip very narrowly 

 dark brown ; tarsi whitish, the two terminal segments becoming more 

 infuscated. 



Wings with a grey suffusion, veins rather pale. Venation (see Plate 

 xiv, fig. 9) : Sc long, ending about opposite the middle of Rs, Sc2 at its 

 extreme tip, the terminal portion of Ri beyond the cross vein r, 

 atrophied. 



Abdomen long, uniform dark brown, the sternites rather brighter. 



Holotype, 9 , Songo, Bolivia, in the Hungarian National 

 Museum. 



From mirabilis Osten Sacken (i), the only described species 

 with dark femoral and tibial apices, this species differs as fol- 

 lows : Sc much longer, ending near the middle of Rs instead 

 of just beyond its origin ; the atrophy of the tip of Ri distin- 

 guishes omissinervis from all of the described forms. 



Genus Toxorhina Loew. 

 1851. Toxorhina Loew.; Linnaea Entomologica, vol. 5, p. 400. 



Toxorhina brasiliensis Westwood. 



One $ from San Bernadino, Paraguay. Fiebrig, 1908. 



Genus Atarba Osten Sacken. 



1869. Atarba Osten Sacken; Monographs of the Dipt, of N. Am., 

 vol. 4, pp. 127, 128. 



Atarba varicornis, sp. n. (PI. XIV, Fig. 10). 



Antennae very long, annulated dark brown and yellowish ; femora 

 unicolorous ; wings without a stigmal spot ; valves of the ovipositor 

 very powerful; abdominal tergites dark brown. 



Female. Length, 4.2 mm. ; wing, 4.9 mm. 



Rostrum yellowish, the palpi a little darker ; antennae with the scapal 

 segments dull yellow, flagellum with the basal half of each segment 

 light yellow, the apical half abruptly dark brown, the terminal two or 

 three segments uniformly brown; front and occiput dull brownish yel- 

 low, the vertex a little darker brown. 



(i) Osten Sacken, Cat. Dipt. N. Am., p. 220 (1878); Williston, 

 Trans. Ent. Soc. Lond., pt. 3, p. 291, fig. 65 (1896). 



