SOUTH AMERICAN DIPTERA. 263 



longer than the two nearly eqnal preceding joints together; in color nearly 

 black, the first joint red at base. Front black, not shining; ocelli situated on a 

 prominent tubercle. Occiput densely light poUinose. Thorax black, nut shin- 

 ing, the pleurpe sparsely clothed with fine white tomentum. Abdomen black, 

 the third and fourth segments wholly and densely clothed with bright j'ellow 

 pubescence or tomentum. Legs pitchy black, the four hind tarsi, except the two 

 terminal joints, yellow. Wings cinereous hyaline, the stigma yellow; first pos- 

 terior cell closed near the costa, the last section of the fourth vein nearly straight. 



One specimen, Chapada. I susi)ect that the mesonotum has been 

 deprived of its tomentum, to some extent, at least; there remains a 

 small spot of yellow tomentum near each post-alar callus ; in front of 

 the scutellum there may have been a distinct band. The antenna" 

 are about as long as the middle femora. The eyes do not show any 

 markings after restoration over wet sand ; they ai'c jirobably uni- 

 colorous in life. 



15. Melanostonia longiooriiis n. sp. 



%i 9. — Length 8 mm. Antenna? elongate, face pollinose on the sides with 

 punctate spots ; third segment of the abdomen with two yellow spots. 



% . Mesonotum bronze green. 



9. Front with two oval, opaque spots; mesonotum lilue, with three black 

 stripes ; front tarsi dilated. 



9 . — Face in profile nearly straight below the antennte to within a short dis- 

 tance of the oral margin ; shining black, sometimes bluish ; in the middle and a 

 stripe on the cheeks bare; on the sides rather thickly pollinose, leaving numer- 

 ous small, round, bare spots. Antennae brownish yellow, the third joint more 

 brown ; slender, nearly as long as the front ; first and third joints of nearly equal 

 length, the second short. Front below and at the vertex shining, bluish black; 

 below the rather prominent ocellar tubercle an oval opaque spot on each side on 

 a grayish pollinose ground. Thorax metallic blue, but little shining ; mesonotum 

 thinly pollinose, with thiee black stripes, the median one slender and dilated 

 triangularly in front of the scutellum ; the lateral ones beginning broadly at the 

 suture and attenuated posteriorly. Pleurai light pollinose. Scutellum shining 

 metallic blue. Abdomen black, moderately shining, the first segment and the 

 anterior angles of the three following segments shining blue ; third segment with 

 two reddish yellow spots in front. Wings hyaline, subcostal cell yellowish 

 brown ; the extreme tip of the wings brownish or blackish. Legs yellow, or 

 reddish yellow; hind femora, except the base and hind tibiae, deep brown ; four 

 front femora more or less brownish at the base; distal joints of four hind tarsi, 

 and all of the front pair, brownish ; front tarsi moderately dilated. 



% . — Mesonotum and scutellum shining metallic bronze green, with only feeble 

 indications of stripes; pile longer, more abundant and yellow. Abdomen less 

 shining, the first and fourth segments shining green. Wings tinged with yellow. 



Five females and one male, Chapada. This species has the general 

 habitus of a Melanostovia, notwithstanding the differences in the 

 structure of antenuie and abdomen. In both sexes the abdomen is 



