AET. 1 NEW DIPTERA FROM SOUTH AMERICA ALDRICH 25 



scutellum) ; dorsocentral 3, 3; humeral 4; posthumeral 1; presutural 

 1; notopleural 2 (surrounded by hairs); supraalar 3; intraalar 3; 

 postalar 2; sternopleural 2, 1; scutellum as mentioned. Calypters 

 white, the rim blackish on inner edge. Abdomen broad and rather 

 deep, the genital segments giving it a truncate appearance, sub- 

 shining black but the intermediate segments with some thin white 

 pollen in oblique view; bristles of fourth segment large and erect 

 anteriorly, becoming denser and smaller on posterior part. First 

 genital segment rather 

 prominent, d e c 1 i v ous, 

 second more bulging. ^^ 

 Inner forceps united ' ""^^s^rr^it 

 into a slender black or- 

 gan slightly bent for- 

 ward at tip; outer for- 

 ceps also black and slen- ^"^^ ^- — riRioNA fasciculata, new species, hind leg 



'^ . T , OF MALE. (Drawn by C. T. Greene) 



der; penis and claspers 



black but not distinctly visible in the only specimen. Legs rather 

 stout, front claws and pulvilli a little elongated; mid tibia with 

 several bristles on outer front side, one at the middle fully half as 

 long as the tibia, and one of almost the same length on the flexor 

 side; hind tibia besides those on outer hind side has three on outer 

 front and the same on inner hind. Hind coxa with a fasciculus of 

 long black hairs on inner edge ; hind femur curved, with a prominence 

 at two-thirds of its length below, bearing a remarkable fasciculus of 

 long black hairs. (Fig. 2.) Wing grayish, gradually becoming more 

 clouded toward base. 



Female.— Front at vertex 0.30 of head width, very gradually 

 wider anteriorly. Genital segments not in position to examine, but 

 evidently without piercer. Hind femur without fasciculi. 



Length, 6.2 mm. 



Described from one male and one female collected at Marga 

 Marga, Chile, by Rev. Anastase Pirion, after whom I name this 

 remarkable genus. Also from one male collected by Edwards at 

 Bariloche, Rio Negi'O, Argentina (British Museum) ; and three males 

 collected by Shannon, two at the place just mentioned, the other at 

 Lago Gutierrez, Rio Negro, Argentina. 



Type.— Male, Cat. No. 41385, U.S.N.M. 



O 



