42 DIPTERA 



TABLE OF GENERA 



a. Metatarsus shorter than first tarsal Genus Corethra, Meigen (= Mochlonyx, Loew). 



aa. Metatarsus longer than first tarsal. 



Large species 10 or more mm, tarsal claws bifid . Genus Pelorempis, Johannsen. 

 Small species with simple tarsal claws. 

 Antennae with second segment long . 



Spaces between verticels bare . . ' Genus Sayomyia, Coquillett. 



Spaces between verticels hairy Genus Corethrella, Coquillett. 



Antennae with second segment short. 



Spaces between verticels bare Genus Eucorethra, Coquillett. 



I. Genus CORETHRA, Meigen (not Loew) 



Corethra. Meigen, Illig. Mag. Vol. 2, p. 260 (i8o3). 

 Mochlonyx. Loew, Ent. Zeit. Stett. p. 121 (1844). 



Characters. — Proboscis short in rj< and 9- Palpi twice as long as the proboscis. Last two 

 segments of the antennae longest, segments increase in\size from base to apex. Wings with the cross- 

 veins nearer the base than in Sayomyia; fork-cells long, stems short. The legs have the first tarsal joint 

 (Metat irsus) always shorter than the second tarsal; ungues moderately large, uniserrated. 



Geographical distribution of species. — Three species only known, two in Europe, the other 

 in North America. 



1. C. velutinus, Ruthe, Isis. p. i2o5 (i83i) (Europe). 



Mochlonyx velutinus, Ruthe. 



Mochlonyx effoetus, Walker, Ins. Brit. Dipt. Vol. 3, p. 252 (i85i) 



2. C. cinctipes, Coquillett. The Canad. Ent. p. igo, July (igo3) (North America). 



3. C. culiciformis , De Geer, Mem. Hist. Ins. Vol. 6, p. 372 (1776). 



2. Genus PELOREMPIS, Johannsen 



Pelorempis. Johannsen, Bull. 68 Ent. 18. New York State Mus. p. 402 (1903). 



Characters. — Large species resembling Psorophora in general appearance. Palpi longer than 

 the proboscis, of 4 segments; antennae of i5 segments, the ba=al one disc-like, second short and thick, 

 rest including the apical one small, verticillate with a few hairs of moderate length, no ocelli. Legs long 

 and slender; metatarsus nearly as long as the following four joints taken together; ungues slender, 

 each with a single tooth. Wings long and slender; the margins and veins except the cross-veins and 

 first anal covered with flattened hairs. 



Geographical distribution of species. — A single species only known. 

 1. P. amerkana, Johannsen, Bull. 68 Ent. 18 New York State Mus. p. 403 (igo3). 



3. Genus SAYOMYIA, Coquillett 



Sayomyia. Coquillett, The Canad. Ent. p. 1S9, July (1903). 

 Corethra. Loew (non Meigen). 



Characters. — Hairs of antennae gathered into whorls (verticillate) spaces between the whorls 

 nude. Pilose in 9 \ plumose in tf . First tarsal segment longer than the second; ungues small and 

 simple. Venation typical. The majority of species described as Corethra belong here. 



