ZENILLIA AND ALLIED GENERA — SELLERS 41 



Most of the species of Carcelia possess an inner ventral bristle on the 

 midtibi a and small bristly hairs behind at apex of hind coxa. Carcelia 

 separata lacks both these characters. In a few species there is exhib- 

 ited a tendency to the lack of an inner ventral bristle to become a sec- 

 ondary sexual character. Except for C. separata, all the other species 

 treated in the following key have the hind coxa with small bristly hairs 

 behind at the apex. 



KEY TO THE SPECIES OF CARCELIA 



There are 15 species included in the key, 12 of which are known to 

 occur in the Nearctic realm and one in the Neotropical realm. As the 

 Palearctic species Carcelia separata and C. gnava have been released in 

 the northeastern part of the United States, they are included, but to 

 date there is no evidence to indicate that they are established. It was 

 considered that the systematic value of the table would be increased 

 even if separata and gnava are never recovered in North America ; it 

 will also help to keep the identity of the two species separate in our 

 literature. The Palearctic species of this group are so similar to many 

 Nearctic species that much confusion in their identity has arisen. 

 Sufficient Palearctic material has been examined to place the knowl- 

 edge of the Nearctic species of Carcelia on a firm basis. 



1. Midtibia with one median anterolateral bristle; fore tibia with one or two 



median posterolateral bristles 7 



Midtibia with two or more median anterolateral bristles ; fore tibia with two 

 median posterolateral bristles 2 



2. Sternoplenral macrochaetae two 4 



Sternoplenral macrochaetae three 3 



3. Palpus normal and flat; no discal bristles on second and third abdominal 



segments 1. formosa (Aldrich and Webber) (p. 43) 



Palpus swollen; small or weak discal bristles on second and third abdom- 

 inal segments 2. inflatipalpis (Aldrich and Webber) (p. 45) 



4. Discal bristles or macrochaetae on second and third abdominal segments.— 5 

 No discal bristles or macrochaetae on second and third abdominal 



segments 3. gnava (Meigen) (p. 45) 



5. Frontal bristles on parafacial not nearer to facial ridge than to margin of 

 eye, descending to at least on a level with insertion of arista ; facial ridge 

 usually bristly on move than lowest one-fourth, often ascending to near 

 middle especially in males ; more or less developed discal bristles or macro- 

 chaetae on second and third abdominal segments, more or less irregularly 

 arranged; when viewed from behind inner forceps of hypopygium closely 



approximated " 



Frontal bristles on parafacial nearer facial ridge than margin of eye, descend- 

 ing to at least on a level with base of third antennal joint ; facial ridge 

 usually bristly on lowest one-fourth, sometimes ascending slightly higher in 

 males ; discal bristles on second and third segment approach weak macro- 

 chaetae in size (usually one pair of weak discal macrochaetae on third 

 segment) ; when viewed from behind inner forceps of hypopygium widely 

 separated 4. reclinata (Aldrich and Webber) (p. 48) 



