28 sYRPniu.i:. 



Several groups have been suggested, of vvliich none have met 

 with anything Hke universal approval. Verrall* treats effectively 

 of the attempts at subdivision, which need not be recapitulated 

 here, since they are not generally adopted. He also thinks that 

 different relationships exist among these insects, judging from 

 the very different larval habits of some of those the life-histories 

 of which are more or less known. 



Tahle of Genera f, 



1. Face flat or retreating {i. e. not arched, 



nor with a central knob; rarely (Psilota) 

 produced at upper mouth-edge), being 

 from the prominence of the frous down 

 to the mouth almost parallel with the 

 eye-margin. Eyes and face hairy ; 

 face all blackish or seneous | ; dark- 

 coloured species with no pale mark- 

 ings on head or thorax 2. 



Face with a central knob, or else ai'ched, 

 or produced cone-like and not at the 

 upper mouth-edge only § 3. 



2. Face with upper mouth-edge not ]U'o- 



duced PiPizELLA, Ptond., p. 36. 



Face with upper mouth-edge conspicu- 

 ously produced 7 Psilota, Meig., p. 38. 



3. Face arched, not hollowed below frontal 



prominence ; always moreorlessyellow. Paragus, Latr.. p. 30. 

 Facehollowed below frontal prominence il, 

 produced again to central knoh, or to 

 upper mouth-edge, or to both 4. 



4. Wholly dark species, Avithout pale mark- 



ings ; at most under side of ord nn- 



tennal joint or knees are pale ^ 5. 



Species with pale markings on head, 

 thorax, scutellum or abdomen **. . . 6. 



5. Third antennal joint more or less elon- 



gate ; apical section of 4th vein re- 

 current, about perpendicular to longi- [p- 40. 



tudinal axis of wing ORTHONErRA, Macq., 



Third antennal joint not elongate ; apical 

 section of 4th vein not recurrent ; 

 forming an acute angle with 3rd vein 

 and with longitudinal axis of wing . . Chilosia, Meig., p. 41. 



* Brit. Fhes, Syrphidse, p. 137. 



t The present table is constructed uhiiost entirely from Verrall's table of 

 the European genera. 



+ Two species referred to Pi-pi-eUa have yellowish faces. 



§ In doubtful cases the face and eyes are nearly always bare. 



II Except in some species of SplKerophoria. 



^ Some $ 9 of Melanostoma and nielauoid specimens of IHafychirus, Melano- 

 stoma and Syrphus might apparently fall in section 4 and be mistaken for 

 Chilosia, but the latter genus is known from all others by its eye-margins. 



** Unicolorous fem;\les or nielanoid ones might be mistaken for Chysogaster 

 or Chilosia, but species of the former are more or less metallic, and those of 

 the latter genus possess eye-margins. 



