THEREVID.E. 



207 



Metaphragma is, I believe, purely a specific character, 

 and will not be found in allied species. 



Fig. 80. Therevidae. 1, Tabuda, head; 2, Psilocephala, wing: 3, 

 Psilocephala, antenna. 



TABLE OF GENERA. 



1. First antennal joint much thickened and elongate. . . 2 

 First antennal joint not noticeably thickened. ... 5 



2. Head not as broad as long; vertical diameter of the eyes equaling 



the horizontal diameter; eyes of male dichoptic. Nebritus. 

 Head distinctly broader than long. ...... 3 



3. Third antennal joint about one-third the length of the first; fourth 



posterior cell open. ........ 4 



Third antennal joint more or less elongated. . Thereva, pt. 



4. First posterior cell divided by a cross-vein. . Metaphragma. 

 First posterior cell not divided by a cross-vein (f Pachyrhiza, 



? Baryphora) (1). . • . . . . Tabuda. 



5. Third joint of the antennae about four times the length of the first; 



without style; fourth posterior cell closed; front of male broadly 



dichoptic Henicomyia. 



Third joint of antennas not four times the length of the first; fourth 

 posterior cell open or closed. ...... 6 



6. Face bare; usually more bare and shining species (2, 3) {Ozodi- 



ceromyia) Psilocephala. 



Face distinctly pubescent or hairy; usually more pilose and polli- 

 nose species. (Fig. 80; also fig. 15, p. 42, not Rhyphus.) 



Thereva. 



