212 



NORTH AMERICAX DIPTERA 



37. Arista much shorter than the third antennal segment (17). 



Lamprempis Wheeler and Melander 

 Arista much longer than the third segment Porphyrochroa Melander 



38. Face hairy 39 



Face bare 40 



39. Third vein furcate (24) Empimorpha Coquillett 



Third vein simple (36) Neocota Coquillett 



40. Third vein furcate (22, 40) Empis Linnaeus 



Third vein simple 41 



41. Third antennal segment many times longer than wide (45, 52). 



Axelempis Curran 

 Third antennal segment normal Rhamphomyia Meigen 



43. Third antennal segment remarkably lengthened, strap-like, and without 



evident style 44 



Third antennal segment not remarkably long 45 



44. Antennse inserted above the middle of the head Niphogenia Melander 



Antennae inserted below the middle of the head Ceratempis Melander 



45. Antennae situated at the middle of the head, the third segment with a 



short style which terminates in a bristle-like segment. 



Boreodroma Coquillett 

 Antennas situated above the middle of the head, the third segment 

 usually with a long arista 46 



46. Third vein simple 47 



Third vein branched 48 



Empidffi V. — 43 Wiedemannia hamifeia; 44, Clinocera binotata; 45, Axelempis fulvithorax ; 

 46. Chersodromia hougrhi ; 47, Chelipoda elongata; 48, Parathallasius aldrichi ; 49, Platypalpus 

 coquilletti. 



