110 SYRPHID®. 
12 (7) Hind femora greatly thickened, often 
flattened at the tip and bearing a 
prominent denticulate plate below, 
Merodon-like ; vertical triangle in 
the male broad, frons in the female 
very broad. 
13 (18) Third antennal joint red or reddish, 
sometimes more or less infuscated, 
but never black ; ocelli arranged in 
au equilateral triangle. 
14 (15) Abdomen more or less red on the 
sides near the base ; front coxee and 
four anterior les entirely red ; 
wings hyaline with pale stigma .. ainecerus, Speis. 
15 (14) Abdomen entirely black, or at the 
most with yellow spots on the 
second and third seements; front 
cox black; fore legs more or less 
black; wings infuscated towards 
the middle, with blackish stigma. 
16 (17) Abdomen with broad yellow spots on 
the second and narrower ones on 
the third segment; third antennal 
joint small, dark brown..........  qguadrimaculatus, Macq. 
17 (16) Abdomen with the usual lunule, 
beneath which can be seen a yellow 
ground ; legs often with black tarsi 
also; third antennal joint broad, 
TOG... s:cisiaiatle sss a oeeee ee ete erythrocerus, Loew. 
18 (18) Third antennal joint entirely black ; 
ocelli arranged in an isosceles tri- 
anvle, the ‘anterior ocellus being 
further from the posterior ocelli 
than the latter are from each other. 
19 (22) Scutellum lony, clothed with short 
hair, not ciliated behind, with the 
hind border thin, sharp, and granular, 
not tomentose; thorax shining 
black in front of the suture, without 
yrey pattern; frons in the female 
shining black; abdomen elongate, 
with less distinct lunulee. 
20 (21) Eyes bare; hind femora and tibixe 
flattened, shining black, a!most 
bare; third antennal joint tii- 
angular...... feces cea ieees wo...  triangularis, Hery.-Paz. 
1 (20) Eyes. densely pilose, even in the 
female; hind femora and tibie of 
usual shape, very hairy ; abdominal 
lunule evanescent outwards......  wnicolor, Loew. 
22 (19) Scutellum rather short, clothed with 
long hair, ciliated behind, its hind 
border not sharp, less oranular aud 
crey tomentose ; thorax in front of 
the suture with distinct grey mark- 
ings; frons in fem: Als “densely 
tomentose, the grovnd-colour not 
