DETERMINATION OF GROUPS. 19 



Distinctive Characters." An epitome of the diagnostic characters 

 of each species will be found printed in italics at the commence- 

 ment of the detailed description, which should always be 

 consulted in cases of doubt. 



The dichotomic system is employed in the subjoined Tables, 

 which it is hoped will prove readily intelligible after a little 

 practice. In using the Tables, the Group to which a specimen or 

 species belongs should of course be determined tirst. 



TABLE FOR THE DETERMINATION OP GROUPS. 



1. Hind tarsi entirely dark brown, black- 



ish-brown, or black above (or at least 

 all joints more or less dark ; in G. 



tachinoides, Westw., the extreme tips , 



of the first three joints and the ex- 

 treme bases of the second and third 

 joints are buff, and a larger or smaller 

 area at base of first joint is also paler 

 than remainder of joint, especially 



in 9) I. Glossina palpalis 



Group. 

 Hind tarsi not entirely dark brown, 

 blackish-brown, or black above, but 

 either last two joints alone so coloured, 

 and thus forming a conspicuous 

 contrast with remaining joints, 

 which are entirely pale, or last two 

 joints, viewed from above, con- 

 spicuously darker than first two or 

 first three joints 2 



2. Upper surface of abdomen distinctly 



banded, i.e. ground colour pale (drab- 

 grey, buff, or ochraceous-bufi), marked 

 with very conspicuous, dark brown or 

 clove-brown, transverse bauds, inter- 

 rupted in the median line * II. Glossina morsitans 



Group. 



* N.B.— The abdomen of G. tachinoides, Westw., is banded in this way, 

 but the coloration of the hind tarsi places this species in Group I. 

 Note that in individuals belonging to Group II. {Glossina morsitans 

 Group) the inner extremities of the interrupted abdominal bands are 

 often partially obliterated ; in such cases, however, the outline of the 

 obliterated portions is usually traceable. 



