260 S. W. WILLISTON, M. D. 



of the froDtal triangle the color is opaque, and is clothed with straight, black 

 pile ; in both sexes the ocelli and vertex have black pile; post-orbital cilia white. 

 Across the front part of the thorax, descending on the pleurse, there is a band of 

 yellowish or white pile, like that of the face. Legs black, the knees reddish; 

 the first two or three joints of all the tarsi, except the hind metatarsi, light 

 yellow. Antenufe i"ed at base, the third joint brownish or brown. 



8. Tricliopsoiiiyia polita n. sp. 



% . — Length 7 mm. Mesonotum opaque black ; on the side, behind, and the 

 scutellum metallic bronze black ; pile black. Abdomen narrow, elongate, deep 

 opaque black ; the first segment, the narrow lateral margin of the second and 

 the third, except a large basal triangle, and hypopygium, shining metallic bronze 

 black. Hind femora considerably swollen, but not clubbed ; hind tibise moder- 

 ately dilated ; middle femora of the male with a stout tooth below in the mid- 

 dle. Wings lightly infuscated ; stigma brown. 



9 . — Front wholly smooth and shining metallic greenish black, a small white 

 spot near the orbit above ; ocellar tubercle but little projecting. Mesonotum and 

 scutellum wholly shining bronze black, the sides and posterior part white pubes- 

 cent. Abdomen oval, wholly moderately shining greenish black, the sides and 

 posterior part white pubescent. Middle tibife without tooth-like projection. 

 Wings cinereous hyaline, the stigma pale yellow. 



Two specimens, Chapada. "Will be distinguished in the male by 



the tooth-like projection of the middle femora ; in the female by the 



smooth front. 



9. Ti'ieliopsoiiiyia puella n. sp. 



'^ . — Length 6 mm. Ocellav tubercle strongly projecting. Mesonotum shining 

 black, on the disc in front broadly opaque ; pile long, mostly black. Hind femora 

 moderately thickened at tip, slender on the basal three-fourths ; hind tibiae ex- 

 traorilinarily thickened and dilated, densely black pilose behind. Abdomen 

 opaque black, the first segment slender, hind margin of second, a large triangle 

 on each side of third, the fourth, except a large basal triangle, and the small 

 hypopygium, coppery or metallic black. Wings brown ; on the posterior i)art, 

 and a cross band before the tip, subhyaline. 



9 . — Front above only a little irregular, without distinct swellings. Abdomen 

 wholly shining. 



Four females and one male. Another male differs in having the 

 abdomen narrower, the second and third segments largely yellow 

 jmbescent, and with yellow pile mingled with the black of the thorax. 

 The female agrees with the last-mentioned male in the pubescence 

 and pile, and the more elongate abdomen. 



10. Tricliopsoniyia tuberciilata n. sp. 



9 . — Length 6 mm. Differs from the females of both the preceding species in 

 having on the upper part of the front, below the ocelli, two prominent rounded 

 tubercles forming with the prominent ocellar tubercle, an equilateral triangle; 

 in having a black opaque cross band on the middle of the mesonotum, and in 



