BASED ON A STUDY OF THE MALE GENITAL AUAIATURE. 



31 



the stem of the clasper and takes a course ahnost at right angles to the latter 

 until it reaches the middle line, when it bends suddenly towards the distal margin 

 of the claspers so that a large rectangular projection is formed, the breadth of 

 which is greater than the width of the narrowest portion of the superior clasper ; 

 bristles on the outer lateral portion similar to those in G. lonffipalpia but 

 relatively shorter. Juxta (j) with a very narrow slit on the distal portion. 

 Bristles of the editum (<?) half the length of the superior claspers. Inferior 

 claspers (ic) pointed, basal portions very broad and apparently meeting in the 

 median line. 



The morphological differences between this species and G. lovgipalpis, though 

 they may appear at first very slight, are really well marked and pronounced, as 

 may be gathered from the following table and the accompanying illustrations : — 



Comparative Table of the Morphological Characters of the Superior Cla.^iers, SyC, of 

 G. pallidipes and G. longipalpis. 



Heel or posterior 

 lateral tooth. 



Single long hair on 

 distal marain. 



Inner flange-like ex- 

 tension of superior 

 clasper. 



Longest hairs 

 editum. 



of 



G. pallidipes. 

 Outer lateral margin 

 genei'ally curved in- 

 wai-ds. 



Short and not capable 

 of overlapping hair 

 on opposite clasper. 



Breadth greater than the 

 icidth of the narroivest 

 portion of the stem. 



One-half the length of 

 the superior clasper. 



G. longipalpis. 



Outer lateral margin 

 taking same contour 

 as the margin of the 

 clasper. 



Long and capable of 

 overlapping corre- 

 sponding hair on op- 

 posite clasper. 



Greatest breadth about 

 one-fourth the width 

 of the narrowest por- 

 tion of stem. 



Equal in length to the 

 superior clasper. 



In the paper recently published by me in the Annals of Tropical Medicine 

 and Parasitology (Vol. IV., p. 370) I called attention to the fact that I had 

 examined a single example of what had been considered an authentic specimen 

 of G. pallidipies, Austen, and that it proved to be morphologically identical with 

 G. longipalpis, Wied. In the light of this discovery I felt that the only course 

 open to me was to treat G. pallidipes as a colour variety of G. longipalpis. The 

 specimen in question has, however, proved to be a variety of the latter with pale 

 front and middle tarsi, so that this insect is evidently given to occasional 

 variation in the colour of the tarsi, though at the present moment this would 

 seem to be an isolated instance. 



Thanks to the kindness of Mr. E. E. Austen, of the British Museum of 

 Natural History, I have been able to examine the genitalia of seven males 

 of his G. pallidipes,'^ and it was by the examination of this material that 



■■ All labelled from " Machakos, B. E. Africa. Presented by Tsetse-Fly Committee of the 

 Royal Society per Lt.-Col. Bruce." 



