SYNOPSIS OF NORTH AMERICAN SYRPHID^. 237 



bifide de chaque c6t6, 4« avec luie baiule semblable legeremeut elargie 

 en arriere; pieds noirs, geuoux, base des tibias auterieurs et interme- 

 diaires, fauves; ailes hyaliues, stigmate d'un testae6 pale. 1 specim. — 

 Bigot, 1. c. ^ 



Xylota pachymera. 



Xi/lota pachjimera Loew. Centur., vi, 54. 



Habitat— Cuba (Lw.). 



9 . Length, 9""". Blackish steel-blue, abdomen with four luteous spots 

 sometimes with only two, rarely with none; antennte fuscous-black, 

 third joint oblong; face carinate; hind femora remarkably thickened; 

 tip of hind tibise produced into a tooth. 



Head blackish steel-blue, front with a median fascia and the face 

 white pollinose. Face carinate. Thorax metallic bluish-black, shin- 

 ing, with two more bronze-colored approximate stripes of the dorsum 

 more thickly clothed with pile. Abdomen blackish steel-blue, some- 

 times more bronze colored ; second segment with two oblong luteous 

 spots, not attaining the margin of the segment, rarely obsolete; front 

 half of the third segment shining, sometimes with two small luteous 

 spots, posterior part black and subopaque; the following segments 

 wholly shining, blackish steel-blue, rarely blackish bronze; venter lute- 

 ous, last segments metallic. Femora blackish steel-blue, the hind pair 

 remarkably thickened ; front and middle tibise, except the whitish base, 

 fuscous black, hind pair, except the white base, black, strongly arcuate, 

 produced into a tooth at the tip; front tarsi whitish, hind tarsi black- 

 ish fuscous, the last two joints of all black. Wings blackish cinereous, 

 stigma fuscous. 



Xylota pretiosa. 



Xi/Iotu preliom Loew, Wien. Eur. Mouatschr., i, 39; Centur., vi, 53. 



Habitat. — Cuba (Lw.). 



9. Length, 10""". Light green-bronze, very shining; abdomen steel- 

 blue, with four hght yellow spots; the front and middle tibiae and the 

 basal third of the hind tibiie, and all the tarsi, except the last three 

 joints, whitish yellow. 



Face greenish bronze, white pollinose. Anteunaj black, third joint 

 subrotund, arista of the same color. Front greenish bronze, white pol- 

 linose. Vertical triangle narrow, greenish steel-blue, shining, sparsely 

 black pilose. Ocelli remote from the occipital margin. Thorax very 

 light greenish bronze, near the hind margin somewhat steely blue, on 

 each end with short white pile, between the wings clothed with black. 

 Scutellum steel blue. Abdomen light steel-blue; second segment 

 with two pallid yellow spots, of which the posterior angles extend to 

 the lateral margins of the abdomen, posterior part of the segment 

 blackish- violaceous, opaque ; third segment with two ^transverse pallid 



