SYNOPSIS OF NORTH AMERICAN SYRPHID^. 33 



5. — Third joint of antennae nearly rounded 7 



Third joint elongate, or at least twice as long as wide ; tip of fourth vein less 

 remote from anterior cross vein than is the posterior angle of the cell in- 

 cluded 6 



6. — Third joint of antennae elongate stigmata 



Third joint of antennte short uigrovittata 



7. — Front of female lightly rugose lata 



Front of female strongly rugose nigripes 



Chrysogaster nigripes. (Plate II, figs. 10, 10a.) 



Chrijsogasier nigripes Loew, Centur., iv, 60 (male). 

 Orthoiieiira untuJata Loew, Centur., ix, 80 (female), 

 f Chri/soijaster Antitheus Walker, List, etc., iii, 572. 



Habitat. — Oonuecticut, ]S"ew York, New Jersey, North Carolina!. 



9,S. Length, 7 to 8°"". Eyes unicolorous. Legs wholly greenish 

 black. Wings a little blackish, more nearly hyaline near the base and 

 posterior part, more or less clouded on the outer part, esi)ccially in the 

 end of the marginal, sub-marginal, and first posterior cells; stigma di- 

 lutely brownish ; the last section of the fourth vein very oblique, a lit- 

 tle convex outward near the angle, and then more broadly concave, the 

 tip joining the third vein in a right angle. First two joints of antennae 

 very short, reddish yellow ; the third round or a little oval, reddish 

 yellow, the upper border darker. Head wholly shining, except a broad 

 white dusted cross-band on the upper part of the face just below the 

 antennsB. 



S. Head metallic bluish green, shining; antennae very small. Frontal 

 triangle very large, swollen, with a longitudinal depression. Face in 

 profile gently concave, distinctly tuberculate below the middle, the 

 epistoma not at all prominent. Dorsum of thorax opaque black, with 

 numerous small, greenish, more shining s^iots, which on the sides be- 

 come confluent, forming stripes. Disk of abdomen deep opaque black, 

 the margins shining brassy green, except at the incisures of the second 

 and third segments, where the black may extend narrowly to the mar- 

 gin. 



? . Deep bluish green, the head and thorax sometimes a deep cobalt 

 blue. Face very concave and prominent below, in profile very dis- 

 similar to that of the male. Third joint of the antennae much larger 

 than in the male. Front broad and long; on the sides strongly rugose, a 

 narrow longitudinal space in the middle smooth. Abdomen shining, but 

 less so on the disk, the first segment, the hind margin of the second 

 and third segments, and a rather broad, less distinct stripe, reaching 

 nearly to the tip of the fourth segment, opaque black. 



Four males and five females. In four of my specimens, both male and 

 female, like specimens Loew described, the second and third segments 

 of the abdomen are in large part sordid yellowish, and the wings may 

 almost wholly lack the blackish clouds. All but one of my specimens 

 were taken together from the same bush of Prunus virginianus on June 

 25. That they belong together I do not have the slightest doubt. Very 



