26 



these lobes giving rise towards the outer side to a small appendage 

 consisting of a single segment, in the shape of a short and slender, 

 squarely truncate, rigid and chitinised process, of a blackish-brown 

 colour. 



"The pseudo-cephalic aspect of adult Glossina larvae is therefore 

 closely comparable to that of the larvae of Thrixion studied by Pantel 

 (1898, 1909), and consists in a more advanced reduction of the condition 

 normally met with in the acephalous Muscid larvae. In the young 

 larva the head is much more prominent, and its external conformation 

 is more easily perceptible." 



" The larva of Glossina morsitans," writes Dr. Kinghorn (79), 

 " resembles those of other species of the genus which have been 

 described. 



" It is a small, elongated maggot, characterised by the black tumid 

 lips which spring from the last segment. The body is composed of 

 twelve segments, 1 and is widest and thickest at the junction of the 

 posterior and middle thirds, whence it tapers more noticeably towards 

 the pointed anterior end. The tumid lips are placed slightly dorsally 

 and rather obliquely to the long axis of the body, so that they are 

 directed backwards and upwards as the larva moves about. In 

 colour it is a dull yellowish-white with a slightly dusky tinge, which 

 becomes more pronounced during the wave-like contractions of the 

 body. When examined under a pocket lens, the integument is seen 

 to be very finely mammillated, and these mammillae have a dark 

 tint, which imparts the general appearance of duskiness mentioned 

 above. 



" From the first segment two minute black bristles, about 0-5 mm. 

 in length, project. These are parallel to one another, and are situated 

 laterally on either side of the middle line. On magnification they are 

 seen to be club-shaped, and are the representatives of the antennae. 

 Between them lies the mouth, the lips of which are directed dorso- 

 ventrally, and are blackish in colour. A trachea can be traced, on 

 either side, as a retractile tube extending from the base of the tumid 

 lips to about the central portion of the body, while on the mid-ventral 

 line, at the junction of the eleventh and twelfth segments, the anus 

 is represented by a small, round, black spot. 



"The tumid lips are characterised by a row of short longitudinal 

 striations along the basal portion, from which spring two knob-like 

 prominences, rounded externally, and separated by a comparatively 

 deep sulcus. Internally they are hollowed out to form a small cavity, 

 on either side of which lies one of the spiracles. The prominences 

 are beset with small tubercles, and are marked off into three more 

 or less equal portions by two shallow furrows. In colour the tumid 

 lips are jet-black." 



As regards the larval stage of Glossina brevipalpis, Austen (3) 

 writes : " The newly extruded larva, which is of the usual Glossina 

 type and shape, and, as stated by Stuhlmann, measures from 9 to 

 10 mm. in length by 2 to 3 mm. in width, is, with the exception of the 

 hindmost segment, pale yellowish-white in colour, with the surface of 

 the integument of the first eleven segments of the usual finely granular 

 and shagreen-like texture ; the last or twelfth segment, 2 which bears 

 the tumid lips or anal protuberances, is, as in other Glossina larvae, 

 deep black. The anterior portion of this segment is encircled by a 



x The actual number of segments is thirteen (vide supra, p. 25). 

 2 Really the thirteenth segment (cf. supra] . 



