SYNOPSIS OF NORTH AMERICAN SYRPHID^. 199 



ish pollen, the cheeks bare and shining. Antennae reddish-brown. 

 Frontal triangle more thickly clothed with yellowish dust. Thorax and 

 scutellnm very thickly clothed with opaque, ochraceous pollen, leaving 

 only a faint, slightly brownish, median stripe ; pile abundant, not very 

 long, wholly yellow. Pleurae black, lightly dusted, moderately shining, 

 except a brown stripe down the middle, which is thickly gray polliuose 

 and gray pilose. Abdomen brownish-black, wholly shining ; pile yel- 

 low, broadly black pilose on the middle of the fourth segment behind. 

 Legs black ; coxae rather thickly gray polliuose, the knees narrowly on 

 the Iront legs, knees and base of tibiae on the middle and hind legs and 

 their tarsi, light yellow, the extreme tip of four hind tibiae sometimes 

 yellow, and the front tarsi somewhat reddish below. Wings distinctly 

 infuscated, especially beyond the anterior cross-vein ; faint clouds on 

 all the cross-viens. 



9 . Face concave ; front of moderate width, thickly luteous polliuose 

 a large black spot above the antennae black, shining, vertex black. 

 Loew, 1. c. 



I have two male specimens from Mr. E. Keen, of Philadelphia. Loew 

 describes the abdomen as " shining black, obsoletely bluish." 



TEUCHOCNEMIS.* 



Tuechoenemis Osten Sacken, Bull. Bnff. Soc. Nat. Sci., iii, 58, 1876; Cat. Dipt., note 237, 

 p. 250. 



Eather large, elongate, moderately pilose species, black and yellow. 

 Head short ; face not tuberculate, not produced ; the margin of the 

 cheeks forming not much more than a right angle with the plane of 

 the occiput. Antennae short, third joint transverse ; arista bare. Legs 

 stout, hind femora thickened, especially in the male. Hind tibiae arcu- 

 ate and provided with a stout, internal, median spur in the male. Mar- 

 ginal cell of wings open, third vein with a moderately deep curve into 

 the first posterior cell. 



Type of genus, T. Uturatus Loew, l!forth America. 



This genus cannot be separated easily from Mallota, and may have 

 to be abandoned. The character upon which Osten Sacken based it, 

 was the peculiar sinir on the internal part of the hind tibiae ; but, as 

 will be seen, this character occurs, apparently as only a dimorphism, 

 in Mallota cimhidformis, and hence has no value here as a distinguish- 

 ing mark. The species are much more bare than in our species of 3fal- 

 lota, and the general habitus, especially of T. bacuntius, is very different. 

 The last species reminds one forcibly of the more Milesiali^e forms. 



TABLE OF SPECIES. 



Abdomen wholly black lituratus 



Abdomen in large part yellow or luteous Bacuntias 



Tevxo'^, armor; nvrjitri, tibia. 



