28 



ZOOLOGICAL EESULTS OF THE EUWENZOEI EXPEDITION. 



The median spermathecal sac is slender as in that species and is straight or nearly so 

 in its course beneath the nerve-cord, not much convoluted as in the allied Polytoreutus 

 si/lvestris *. Anteriorly the sac passes into the fourteenth segment near to the anterior 

 wall of that segment vrithout any change. Arrived there it ends in two diverticula of 

 short extent. These diverticula are apparently of much shorter extent than in any of the 

 species Polytoreutus Mrimaensis, P. usindjaensis, and P. sylvestris, whose spermathecal 

 apparatus is built upon the same plan as that of P. rimenzorii. Michaelsen, as a matter 

 of fact, does not differentiate, except in the case of P. usindjaensis, between each 

 diverticulum and the oviduct with which it becomes continuous, which in fact opens 

 into it according to my interpretation of these various structures in the genus 

 Polytoreutus f . In the figure annexed hereto this arrangement is rendered plain. The 



Text-fis. 3. 



Spermathecal sac of Polytoreutus ruwenzorii. 

 d. Diverticulum of sac. o.d. Oviducal pore. 5 . Spermathecal pore. 



sudden diminution of the cgecum of the spermathecal sac (text-fig. 3) where it is 

 continuous with the oviduct is obvious. Moreover, the oviduct is extremely long as 

 compared with that of some other species, and is much coiled. Much more so is this 

 the case with Polytoreutus ruwenzorii than with any of the three species mentioned 

 as coming nearest to it in respect of the spermathecal sac and its forward diverticula. 

 But apparently these three species do agree with P. rimenzorii in having a much longer 

 oviduct than in many other species of the genus. There is a further point of agreement 

 between the new species described in the present paper and the three East- African 



* Where, however, it is also occasionally less convoluted, perhaps in less mature individuals (Michaelsen, 

 loc. cit. pi. ii. fig. 23). 



t P. Z. S. 1902, vol. ii. p. 206 et seq. 



