78 PROCEEDINGS OF THE ACADEMY OF [Part 1 



Female. — Length about 4.6 mm.; wing 4.5 mm. 



Rostrum and palpi dark brown. Antennae with the scape dark 

 brown; flagellar segments orange-yellow, on the outer half of the 

 organ passing into brown; flagellar segments provided with very- 

 long verticils in the male. Head light yellow, the vertex with a 

 large median dark brown mark. Pronotum yellow, dark brown 

 medially, the scutelluiii light sulphur yellow. Mesonotum dark 

 brown, the scutellum narrowly margined posteriorly with obscure 

 yellow. Pleura deep purphsh brown, sparsely pruinose; dorsal 

 sclerites obscure brownish yellow; a very conspicuous, moderately 

 broad yellow longitudinal stripe extending from the posterior face 

 of the fore coxae, passing above the mid and hind coxae to the 

 base of the abdomen. Halteres yellow, the base darker; knobs 

 broken. Legs with the fore coxae purplish brown with a yellow 

 spot on the posterior face; mid-coxae purplish brown; posterior 

 coxae obscure yellow, only slightly darkened basally; trochanters 

 obscure yellow; femora pale yellow with a narrow brown subter- 

 minal ring; the fore legs are broken but the femora are probably 

 dark brown as in this group of species; tibiae and metatarsi yellow, 

 the tips narrowly infuscated; remainder of the tarsi dark brown. 

 Wings with a strong grayish tinge; cells C, Sc and most of 7?i china- 

 white; stigma oval, brownish gray; veins pale brown, the costa 

 china-white. Venation: Sci ending far before the origin of Rs, 

 this distance being greater than the length of Rs; Rs short, strongly 

 arcuated at origin; cell 1st M2 open by the atrophy of the outer 

 deflection of M3; basal deflection of Cui at the fork of M. Abdomen 

 dark brown, the tergites narrowly margined posteriorly with obscure 

 yellow, broader on the posterior segments; sternites more uniformly 

 brown. Male hypopygium (Plate IV, Fig. 1) with the pleurites 

 rather short and stout, shorter than the longest pleural appendage; 

 pleural appendages four in number ; the longest or ventral appendage 

 is a slender, slightly curved, chitinized arm that tapers gradually 

 to the rather blunt apex, near the base on the inner face with a 

 prominent, acute spine that is about two-fifths as long as the apical 

 point; the second appendage is an apical, elongate needle-like rod 

 directed proximad, tapering to the acute blackened point; third 

 appendage elongate-triangular, the apex a slightly curved black 

 spine; the fourth or dorsal appendage is a pale fleshy lobe, roughly 

 triangular in form, the apex produced into a cylindrical arm, this 

 arm and the proximal face of the appendage set with about seventeen 

 mostly powerful bristles. The penis-guard is a small, feebly chitin- 

 ized structure that is subtended by the much longer gonapophyses, 

 these appearing as two dehcate setigerous cushions. 



Habitat. — Peru, Argentina. 



Holotype, c^, Iquitos, Peru, May 18, 1920 (H. S. Parish). 

 Allotopotype, 9 , May 11, 1920. 



Paratype, c^, Famailla, Tucuman, Argentina, October 12, 1920 

 (V. Weiser). 



