1913.] M. Bkzzi : Indian Trypaneids {Fruit-Flies). 57 



13. Supra-alar bristles (sa.) : three; the anterior, just behind the suture, is very 

 rarely wanting, the posteriors, one above the root of the wing and one on the postalar 

 callus are always present ; these last are also called postalar bristles. 



14. Propleural bristle (pp.) or prothoracic: near the prothoracic stigma, usually 

 wanting. 



15. Mesopleural bristles (mpl.) : one or two on the posterior border of the 

 mesopleura, sometimes accompanied with some bristly hairs. 



16. Pteropleural bristle (pt.) : one on the pteropleura, under the root of the 

 wing, usually strong, but sometimes weak. 



17. Sternopleural bristle (st.) : on the sternopleura, below the stemopleural 

 suture, very rarely wanting. 



The pubescence of the thorax is moreover of some importance, being more or 

 less distinct, black or yellow, and sometimes very strongly developed. 



Scutellum. — The form is important, its surface being flattened or convex, 

 sometimes swollen; in general shape it is triangular, semicircular or trilobate. It 

 usually bears two pairs of bristles. 



18. Basal bristles : a pair, usually stronger than the apical pair, divergent, very 

 rarely wanting. 



19. Apical bristles : a pair, usually weaker than the basal, parallel, converging 

 or even crossed, often wanting. 



There is also, rarely, an intermediate pair of bristles, between basal and apical. 



Abdomen. — Narrow and elongate, or broad and short; narrowed at the base 

 or even pedunculate; the first two segments fused together or distinct; with or 

 without lateral and apical bristles. Male genitalia usually not prominent. Oviposi- 

 tor with the basal joint flattened or tubular; -short, long or very long. 



Legs. — Short and robust, or long and slender; fore femora rarely thickened, 

 with a row of bristles below, which is very rarely wanting ; middle tibiae with one 

 or two spurs ; hind tibiae with or without a row of bristly hairs or even pectinate ; 

 some African species have pinnate legs. 



Wings. — Narrow, broad or very dilated. Costal bristle wanting, more or less 

 developed or even double. Stigma short, long or very long. 



Very important characters are taken from the lengthy direction, form and posi- 

 tion of the longitudinal and cross-veins, and from the form and length of the 

 cells. 



The longitudinal veins are distinguished as follows (fig. 3) : — 



1. Costal vein (Costa, C.) : ending at the fourth vein, more or less thick- 

 ened, ciliated over its whole length. 



2. Auxiliary vein (Subcosta, Sc.) or mediastinal vein of Schiner : thin and more 

 or less short, quite distinct, or very near the front vein and indistinct. 



3. First longitudinal vein (Radius i, R^) or subcostal vein : usually bristly over 

 its whole length, not reaching the small cross- vein, or reaching it or passing 

 beyond it. 



4. Second longitudinal vein (Radius 2 + 3, R.^3) or radial vein : straight, bent 



