24 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 78 



Abdomen dark brown, second to fourth segments with a yellow 

 triangle on each side reaching the hind margin laterally; first seg- 

 ment distinctly white at the sides, with stout black bristles, second 

 segment with a single row of erect, black bristles; fifth segment 

 mostly brown; sixth segment very narrow, blackish; seventh also 

 blackish. Genitalia pale yellow, the posterior forceps of soft 

 appearance, strongly hooked at the anterior end. 



Front and middle legs pale yellow, the tarsi only a little darker; 

 hind femora yellow with two rather narrow and distinct dark annuli, 

 the erect pile on the inner and lower surface is longer than in any 

 of the other species but extends only to the middle of the femur; 

 basal third of the femur strongly shining; hind tibia brown with 

 a whitish ring on penultimate fifth, not very striking, its flexor side 

 with numerous, short, erect hairs on the apical half ; hind tarsi brown. 



Wing brownish, first posterior cell wider than submarginal; second 

 vein short, tip nearer the base than the anterior end of the hind 

 cross vein. Petiole of first posterior cell joining costa almost exactly 

 at the tip of the wing, the last section of the fourth vein being 

 nearly straight. 



FeTnale. — Ovipositor about as long as remainder of abdomen; 

 black, yellow at incisures and apex ; the short basal segment yellow. 

 Hind femora not shining and hind tibiae brownish without annulus. 



Length, male 5 mm., female 4 mm. to ovipositor, which is 2 mm. 



Described from two males and one female; one male and the 

 female are from Kartabo, British Guiana (received from Canadian 

 National Collection), the other male, which is headless, is from La 

 Suiza de Turrialba, Costa Rica (Pablo Schild, received from Prof. 

 A. L. Melander). In this specimen the femora are not shining on 

 the basal third ; the male from Kartabo is taken as the type and the 

 other specimens show slight differences which in more material 

 might possibly prove specific. The type is returned to the Canadian 

 National Collection. 



Allotype.— F^m^ilQ, Cat. No. 43032, U. S. N. M. 



STYLOGASTER INDISTINCTA. new species 



Male. — Frontal triangle very large, occupying almost the entire 

 front, its apex broadly touching the lunule and leaving only a nar- 

 row strip on each side which is dark brown, together with a slight 

 extension of the silver of the face on the lower part of frontal orbit. 

 First antennal joint white, second and third brownish yellow, the 

 latter more red below and about two and two-tenths times the 

 second. Proboscis black to the extreme base. Mesonotum dark 

 brown above with indications of two lighter submedian stripes, the 

 dark color almost joins the humerus behind and on the mesial side, 



