SYNOPSIS OF NORTH AMERICAN SYRPHIDX. l'-3 



Abdomen blackish bronze, basal fascia of the tliird and fourth seg- 

 ments, sometimes also of the tifth, yellow. Wings subhyaline, apical 

 margin and the stigma smoky, the base of the latter black. 



Similar to B. obscuricorms. Head bronze black, lower half of the face 

 yellow ; front, except a median stripe, and face, except the tubercle, 

 thinly clothed with whitish pollen, on the occiput more thickly polli- 

 nose.^ Dorsum of the thorax black brouze, the humeri dilutely yellow- 

 ish. PleuriB dilutely yellowish or a little reddish, below obscurely 

 senescent. Scutellum of the same color as the thorax. Abdomen slen- 

 der, black bronze, near the tip fuscous bronze : third and fourth seg- 

 ments always, fifth frequently, with a basal yellow fascia. Legs yellow 

 or light reddish, hind femora near the tip, the tibise and tarsi nearly 

 wholly, dilutely snbfuscous. Wings subhyaline, lightly cinerescent, 

 veins'blackish"; cross-veins lightly clouded; stigma elongate, smoky, 

 with a basal black spot ; apical margin of the wing smoky. 



Translation of the original, compared with the type specimen at Cam- 

 bridge. 



Baccha obscuricornis. 



Baccha obscuricornis Loew, Ceutur., iii, 26. 

 Baccha angusta Osteu Sackeii, Western Dipt., 332. 



Ba6y:tet— Sitka (Lw.), California ! 



$ 9. Length, 7™™. Head brouze black, front nearly wholly, frontal 

 triangle, and the face except the tubercle, thinly white pollinose, the 

 occiput more thickly so. Antenna) wholly brown or black. Dorsum of 

 thorax and. scutellum bronze black. Pleurae very pallidly testaceous, 

 or above yellow and below subfuscous. Abdomen slender, blackish 

 fuscous, somewhat metallic bronze, the base usually bronze black, the 

 third and fourth segments always, the fifth frequently, with a basal 

 yellow fascia. Legs yellow or dilutely testaceous; the hind femora 

 near the tip, the tibi^, and tarsi almost wholly, subfuscous. Wings 

 subhyaline, lightly cinerescent, veins fuscous black; the transverse 

 veins obsoletely clouded with smoky ; stigma elongate, smoky, with a 

 basal black spot; apical margin and the posterior apical half clouded 



smoky. 



Of the synonymy of B. angusta there caft be no doubt, and its identity 

 with B. elongata of Europe seems very probable. I have only an Euro- 

 pean male for comparison, but I can find no other dififerences than in 

 the color of the antennae, which are red. Loew adds to his description : 

 "A Baccha elongata fronte minus sequali et antennis totis atris dif- 

 fert"; but the third joint of the antennae, in my specimens, as in the one 

 which Osten Sacken described, is brown or brownish, so that this dif- 

 ference loses much of its value, and there only remains the difference in 

 the width of the female front. As I have no- female specimen of B. 

 elongata for comparison, I cannot give any opinion as to the identity of 

 what Loew believed to be two different species. 



