CH/ETOTAXY 



67 



of Glossina ; besides this, the first and second longitudinal veins 

 pursue a different course, and the shape of the posterior basal 

 and of the anal cell is very different. The shape of the wing 

 itself is also different, and the wing is much smaller in proportion 

 in Ili/poderma than in Glossina.^ 



Ch^totaxy op Olossina. 



Cephalic Bristles. — One pair of vertical bristles of large size 

 (the largest and most conspicuous bristles on the head) ; on the 

 occipital region no trace of the pair of bristles termed by Hough 

 (Proc. Acad. Nat. Sc. Philad. 1898, p. 166) the occipito-central ; 

 greater ocellar bristles (ocellar pair of Osten Sacken) small ; 



Prssutu/v/ Bnst/e % 



Prmsutural 

 dorso-centrd Bristle 



2"''dorso<entr3t 

 Bristle \ 



V^dorso-central 



Bristle ... 



Marginal scuteller Bristle ,_ 

 flpicel scutellsr Briitle ... 



\-::~:-j.v^Humeraf S/ist/es 



— / Notoplsural Bristles 



{ofOirschner dnd Hough- 

 posl-hameral cf Osten 

 Sacken .) 



- Supra -alar Bristle 



— Intrs-elar Bristle 



■ Post-a/ar Bristles 



'■^ Inner dorso-central 

 Bristle 



Fis. 10. 

 Diagram of thoracic chnetotaxy of Glossina, dorsal aspect. (X 10.) 



post-vertical pair not differentiated in size from the remainder of 

 the lesser ocellar bristles ; frontal bristles largest below (trans- 

 frontal group of Hough, loc. cit.) ; orhital bristles absent in 

 both sexes ; vihrissal angle (separated by a well-marked and 

 rather wide interval from the oral margin) without a large and 

 conspicuous vibrissa ; vihrissal ridges ciliated to a point on a level 

 with or rather above the middle of the third joint of the antenna. 



TJioracic bristles. —The general arrangement, as can be seen 

 from the accompanying diagrams, is, on each side, as follows : — 



Dorsal aspect {Fig. 10). — Humeral, from 1 to 3 (sometimes 

 apparently 4), the Jowest bristle the largest. Post-humeral 



y 2 



