ART. 9 FLIES OF THE GENUS STYLOGASTER ALDRICH 17 



one and one-tenth times as long as second; mesonotum mostly 

 blackish, but with an ill-defined paler median stripe which is usually 

 quite conspicuous. Humeri white, the area on the mesial side light 

 brown halfway to middle line and the same color extending back 

 above the notopleura to the transverse suture; mesopleura dark 

 brown, gradually lighter close to sternopleura ; posterior part of 

 mesonotum yellowish brown. Humeral 1; notoplural 2; su- 

 praalar 1. Scutellum blackish on the disk, the remainder brown. 

 Metanotum black on median region, sharply defined, the sides 

 yellow. 



Abdomen blackish, the first segment black across the disk, whitish 

 in front and behind and the lateral area entirely white, bearing a 

 large tuft of spiny black bristles ; second segment black, indistinctly 

 paler in the middle, bearing a few outstanding black bristles on the 

 sides at base; second and third segments with an opaque posterior 

 black crossband including about one-third of the length, extending 

 forward in the middle to the anterior edge to form a median stripe; 

 fifth segment more extensively black, shining in certain directions 

 with an indefinite brown area on the sides anteriorly; remaining 

 segments light yellow without any distinct dark markings. The 

 genitalia show a pair of erect compressed lobes side by side, rounded 

 apically, and bearing black hairs behind almost to the tip. 



Front and middle legs very pale yellow, tarsi gradually infus- 

 cated. Front coxae with numerous long black hairs at tip in front 

 and behind. Hind femora black, extreme base and tip and a rather 

 narrow annulus just before the middle white. Tibia pale for about 

 three-fourths of the length, the remainder blackish; hind tarsi en- 

 tirely black. 



Wing uniformly infuscated, the costa with rather longer hairs 

 than usual. Last section of fourth vein considerably bowed so that 

 the first posterior cell is perceptibly wider than the submarginal. 

 Tip of second vein decidedly farther from base of wing than an- 

 terior end of hind crossvein. 



Fevidle. — Front as in male; front coxae with much shorter and 

 fewer black hairs at tip; hind coxae at extreme tip with a single 

 row of rather striking but not very long black hairs. Ovipositor 

 longer than remainder of abdomen, dark yellow at extreme base, 

 then black, a pale yellow ring at the tip of the middle segment, 

 the apex yellow. 



Length, male 8 mm., female about 6.2 mm. to the ovipositor, 

 which is 4 mm. 



Described from seven males and three females collected on Barro 

 Colorado Island, Canal Zone, by C. H. Curran. Type in American 

 Museum of Natural History. 



Paraty^e.—^l^X^, Cat. No. 43026, U.S.N.M. 



