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DR. ROBERT E. MCCONNELL — NOTES ON THE OCCURRENCE 



in the case of females (average of five specimens, 9*5 mm.). In the dried con- 

 dition no doubt these measurements would be somewhat smaller. 



In the female the hind femora and tibiae are lighter than in the male, so that 

 the contrast with the dark tarsi is more marked. So usual is this distinction that 

 one may, in a large proportion of cases, distinguish the sexes by examining the 

 hind leg alone. The last joint of the front and middle tarsi presents a brown 

 colouring near the insertion of the claws, but the rest of it retains the colour of 

 the other tarsi, i.e., yellowish ; under the dark brown bristle-like hairs on the 

 penultimate joint of the same members there may or may not be some browning 

 of the distal portion. In both these cases the middle tarsi tend to be darker than 

 the front tarsi. 



Turning to the male hypopygium I have found the distal appendage to the 

 superior clasper to be distinctly claw-like but not to such an extent as depicted 

 by Newstead. Unless the cover-glass is pressed down tightly these claws are 

 not seen to the best advantage. I have found that the extent of the claw curve 

 was best estimated by examining the unmounted specimen and manipulating it 

 until the lateral surface of the claw was presented to the microscope. 



The angle between the distal third and the proximal two-thirds of the outer 

 surface of the superior claspers I have not found to be as marked as in the 

 description of the type. But as Newstead only examined one specimen this 

 effect may have been exaggerated through some accident in the mounting. In 

 fact, in a few of my mountings one clasper assumed the exaggerated position. 

 The inferior clasper in the mounted specimen has the internal distal portion 

 prolonged into a sickle-shaped process with the tip pointing in the direction of 

 the outer lateral margin. In the unmounted state, however, after following such 

 a course for almost one-third of its length the terminal portion then runs almost 

 vertically from the plane of the hypopygium. When the latter is viewed from 



Diagram of vesica of Glossina palpalis. 

 (1) anterior view ; (2) lateral view ; (a) cephalic process ; (b) lateral processes ; (c) trunk. 



the side these two mast-like processes are well seen. The vesica forms a pro- 

 minent structure. On several occasions I observed its movements in the living 

 fly. The head-like terminal portion nodded energetically, and at the same time 

 the lateral arm-like processes approached each other while the whole structure 

 moved slightly antero-posteriorly. Accompanying this action the inferior claspers 

 approached each other moderately. Sometimes a drop of watery, slightly turbid 

 fluid gathered on the apex of its cephalic process. 



