366 NEW YORK STATE MUSEUM 



Female. Length 2.5mm to 3mm. Head uniform slate-blue, 

 verging to greenish, or cerulean blue in some lights, clothed 

 with silvery pubescence, which becomes longer behind the eyes; 

 parts below the antennae and trophi more densely pubescent, 

 producing the effect of a white face; eyes with a metallic coppery 

 luster; antennae black with very dense white pubescence; no 

 bristles on basal two joints, which are but very slightly tinged 

 with red; joint 1 shortest; joints 2, 3, and 11, subequal in length; 

 joint 3 widest; joints 4 to 9 subequal in length; joint 10 but 

 slightly shorter than joint 11, which is fusiform; joints 3 to 11 

 gradually decreasing in width. Maxillary palpi as long as 

 antennae, blackish, with long, whitish bristles. Thorax slate- 

 blue, with less dense, silvery white pubescence; markings quite 

 distinct, producing the effect of a sculpture, and consisting of 

 three black longitudinal lines, the median narrow, widening a 

 little at the apex, and the outer one curving inward at base, and 

 outward at apex, sometimes reaching to base of patagium, 

 which appears whitish on account of the dense pubescence; on 

 the lateral edges of prothorax are fine black sutures; underside 

 uniform slate-blue, with sparse pubescence; space around the 

 large stigma almost white. Halteres white, very faintly tinged 

 with red. Abdomen nine jointed, joints subequal in length, 

 except the last two, which decrease; markings entirely differ- 

 ent from those of S. pecuarum, formed by velvety black, 

 dark blue and bluish white, almost silvery, colors; the dark blue 

 appears on dorsal surface of the last five segments, spreading 

 from a roundish median spot, on 5 to the immaculate blue of the 

 last two segments; segments 2, 3, and 4 have each a black cross- 

 bar, and 5, 6, and 7, two narrow, black submedian stripes, which 

 disappear almost entirely on 7; the bluish white forms an outer 

 edge to all the black and extends over the whole lower surface 

 of the abdomen, with the exception of more or less well marked 

 black cross lines in middle of each segment; a bluish white or 

 silvery pubescence covers the entire abdomen, but is very sparse 

 on the dorsal parts. Legs brownish black; tarsi almost black, 

 and more or less densely covered with white hairs. Wings, sub- 

 hyaline. Veins bluish white, base ferruginous. Described from 

 many bred and captured specimens. 



Male. Length 1.5mm to 2mm. Very different in appearance 

 from female. Eyes confluent, very large, brilliant coppery; a 

 very marked difference in the size of the facets, those on upper 

 surface being very large and metallic copper, those below and 

 surrounding trophi becoming suddenly small, black, with bronze 

 reflections; trophi reddish black, dwarfed; antennae black, with 

 light, yellowish brown pubescence in front. Thorax above in- 



