18 H. C. EFFLATOUN. 



11 (10) Species dark but not metallic; distinct 



eye-margins present; outer top angles 



of cells R5 and M2 always acute 5 Chilosia.* 



12 (9) Species with pale markings on parts 



of the head, thorax, scutellum and 

 abdomen. 



13 (14) Hind femora thickened and spinose „ Svrttta 



beneath (PI. II, fig. 8) (MILES I ISLE). 



14 (13) Hind femora not thickened or spinose. 



15 (26) Abdomen not conspicuously constricted 



about the base. 



16 (17) Face and scutellum entirely aeneous or 



black (sometimes appearing grey or 

 yellowish from superincumbent dust) ; 

 thorax provided on the sides above the 

 notopleural depression and before the 

 transverse suture with a rather 

 prominent tubercle; cell M2 shorter 

 than cell R5 7 Melanostoma.* 



17 (16) Face and scutellum partly or wholly 



yellowish. 



18 (21) Thorax with bright yellow side lines 



and the pleura with yellow markings ; 

 abdomen narrow, elongate and with 

 parallel sides. 



19 (20) Abdomen narrower than the thorax, 



not flattened, usually longer than the 

 wings; male genitalia very large and 

 orbicular 8 Sph.erophoria. 



20 (19) Abdomen as broad or a little broader 



than the thorax, flattened, shorter than 

 the wings; male genitalia of moderate 

 size 9 Xanthogramma. 



21 (18) Thorax without any bright yellow side 



lines and the pleurae not yellow spotted. 



*So far not represented in Egypt. 



