SYNECHES. 327 



Thorax highly arched ; legs nearly bare 

 except for tibial bristles ; anal cell 

 barely longer than 2nd basal, with 

 nearly truucate tip minutus, Brun., p. 330. 



7. Hind femora brownish yellow rusticiis, Brun., p. 331. 



Hind femora black or blackish brown . . 8. 



8. Smaller species, 2| mm. ; wings nearly 



clear 9. 



Larger species, 3| or 5 mm. ; wings dis- 

 tinctly brown 10. 



9. Stigma very distinct and large, round, 



deep black ; anterior cross-vein at 

 about jj of discal cell ; anterior knees 

 and tips of anterior tibiae and all tarsi 

 wholly yellow ; hind femora consider- 

 ably thickened on apical half insignis, Brun., p. 332. 



Stigma barely appreciable ; anterior cross- 

 vein at about j of discal cell ; only 

 tarsi and extreme tips of tibiae yellow ; 



hind femora not thickened fratellus, Brun., p. 332. 



10. Length 3| mm. ; 1st posterior cell (beyond 



discal cell) distinctly narrowed to- [p. 331. 



wards tip palliditarsis, Brun., 



Length 5 mm. ; 1st posterior cell (beyond 



discal cell) uniformly wide fuscipennis, sp. n., p. 333. 



Acarterus, Lw., with two Indian species is not included in the 

 above table, as its unthickened uuspined hind femora should distin- 

 guish it clearly ; but Harpamerus is included, although the length 

 of the anal ceil should define it with absolute precision. The fact 

 that Prof. Kertesz sinks it in Syneches, however, makes me 

 dubious of its generic validity, Bigot's definitions being often 

 unreliable. 



Of the species tabulated above, sic/natus belongs to Harpamerus, 

 and parvi cell 'ulata to Syndyas, the remainder falling in Syneches. 



Genus SYNECHES, Walk. 



Syneches, Walker, Ins. Saund., Dipt. pt. 3, p. 165 (1852). 

 Acromyia, Latreille, Gen. Crust. Ins. iv, p. 305 (1809). 

 Pterospilus, Rondani, Dipt. Ital. Prod, i, p. 152 (1856). 



Genotype, Syneches simplex, Walk. (South America). 



This genus differs technically from Hybos by the origin of the 

 2nd longitudinal vein being nearer to the humeral cross-vein than 

 to the anterior cross-vein. It is also urged that the 2nd longi- 

 tudinal vein curves forward more in Syneches than in Hybos ; also 

 that the anal cell is almost truncate at the tip in the former and 

 pointed in the latter ; again, that the wings are normally spotted 

 in Syneches and unmarked in Hybos. 



Range. Europe, India, Ceylon, Malay Archipelago, South Africa, 

 North and South America. 



As regards the generic validity of Syneches, there is considerable 

 doubt, the principal character of the position of the origin of the 

 2nd longitudinal vein being much weakened by the existence of 



