2 Mr. R. E. Turner on 



though they have been much used in description, must be 

 used witli extreme cnution in the distinction of species, being 

 far from constant, variations being very common in the 

 comparative length of the second and third aljscissse of 

 tlie radius. Comparatively few Etliiopian species of the 

 genus have been dcsciibcd, and in most of the descriptions 

 important characters — such as the apical segments of the 

 male, the sculpture of the second and third sternites of 

 the lemale, and the structure of the palpi and galea — have 

 }i(jt been noticed. I have not included species from Mada- 

 gascar in this paper, the collection being very poor in species 

 i'rom that island. The occurrence of a species of the sub- 

 genus Culotachytes in Madagascar is, however, interesting. 

 The species 1 have not seen are marked ^. 



Key to the Ethiopian Species of Tachytes. 



dc?. 



1. Mandibles not excised on the ooter mar- 



gin ; median segment striated on the 

 dorsal surface, subrectangular, the 

 apical aniiles not rounded; abdomen 



wlioUy light ferruginous red Subgenus Holofachytes. 



Mandibles deeply excised on the outer \_T. dichrua, Sm. 



margin ; median segment not striated 

 on the dorsal surface, the apical 

 angles rounded ; abdomen other^Yise 

 coloured 2. 



2. MaNillarv palpi five-jointed ; labial palpi 



three-joiuted, vervlong and slender. . Subgenus Otlotachyiex. 3. 

 Maxillary palpi six-jointed ; labial palpi 



four-jointed Subgenus Tachytes. 5. 



3. Four basal tergites densely covered with 



brilliant silver pubescence ; eighth 

 sternite subtruncate, the angles not 

 produced T. marshuUi, Turn. 



Dorsal surface of abdomen covered wirii 

 brilliant golden pubescence; eiglith 

 sternite emarginate, the angles pro- 

 duced 4. 



4. Seventh tergite broadly rounded ; wings 

 subhy aline, with a pale fuscous apical 

 band T. mira, Kohl. 



Seventh tergite truncate at the apex ; 



wings strongly infuscate T. admiralilis, Turn. 



«5. Dorsal surface of abdomen densely 

 clothed with bright golden pubes- 

 cence : head and thorax entirely with- 

 out golden pubescence 6. 



Abdomen not clothed with golden pubes- 

 cence, or if so clothed then with some 

 golden pubescence on the thorax also. 11. 



