PEOBOSCIS, THOEAX, AND ABDOMEN. 13 



rod-like, of the same width throughout, neither swollen nor 

 tapering towards the tips, clothed with short black hairs and 

 minute bristles, a row of some eight to thirteen tiny erect black 

 bristles running along the upper margin, the individual bristles 

 separated by something like regular intervals, and a similar row 

 running along the outside on the basal two-thirds of the palpus ; 

 two somewhat longer and stouter bristles * directed downwards 

 and forwards on the under and outer side immediately before the 

 tip. (For the bristles of the head see below under " Chaetotaxy 

 — Cephalic Bristles.') 



Thorax quadrate, flattened or only very slightly arched above, 

 to the naked eye appearing bare, but in reality sparsely clothed 

 with minute black hairs ; the macrochaetae likewise few in 

 number, arranged as described below under " Chaetotaxy." 

 Transverse suture well marked, forming a groove. Scutellum 

 flattened, with a pale impressed median line, and a darker patch 

 on each side. Markings of the thorax, when completely developed, 

 as shown in Plates I and II {Glossina pal/palis, Rob.-Desv., and 

 c-aUginca, Austen), but in some species very inconspicuous ; if 

 distinguishable at all from the ground colour, taking the shape of 

 grey or brown blotches, streaks, or spots. 



Abdomen also flattened, tapering to the apex ; dorsum of the 

 second segment with a pair of, more or less distinct, longitudinal 

 grooves or impressed lines, one on each side of the middle line, 

 converging towards the hind border of the segment and thus 

 enclosing a more or less lanceolate area, which is sometimes paler 

 in colour than the remainder of the segment ; dorsum of the 

 abdomen thinly clothed with minute and exceedingly short, 

 appressed black hairs, which on the basal angles of the second 

 segment become longer and erect, and on the hind margins of the 

 following segments, from the third to the fifth, take the shape of 

 fine black bristle-like hairs, especially on the apical angles, where 

 they are longest and stoutest ; hind margin of the sixth segment, 

 and also that of the seventh in the female, with a complete row 

 of longer bristle-like hairs ; seventh segment in the male wath an 

 especially conspicuous transverse row of black bristle-like hairs or 

 fine bristles on each side of the median line beyond the middle. 

 The male hypopygium'\ highly characteristic in shape (see Figs. 14 

 and 15, pp. 50, 51), more or less oval and tumid, its longer axis lying 



* In dried specimens these are often missing — one at least is frequently- 

 indistinguishable. 



t The modified eighth abdominal segment, to the inner and concealed 

 surface of which the male genital appendages are attached. 



