(96) 



Thr next two sclerites, which we {iropose to cull the iidraedian, are roniuled at 

 the apex, which is membranons, though elsewhere the}- are chitinised, and their 

 lateral margins bear on their surface an elongate incrassation. The two admedian 

 plates are much nearer together at their base than distally, their inner margins 

 being distinctly divergent. In the gap tlins formed are another pair of sclerites 

 whose inner margins are straight, while the outer margins are nearly evenly 

 curved. These median flaps (MF.) project from the dorsal side (i.e. inner surface) 

 of the admedian plates, to which they are joined proximally where the dotted 

 outline is double in the figure. In an unmounted example these two plates 

 appear like a dark elliptical ring showing through the chitin of tlie admedian 

 plates of the seventh sternite. 



The admedian sclerites are placed towards one another in roof shape, the 

 segment being centrally convex. The median flaps are densely covered with hairs 

 of type 1, the liairs im the admedian jdates also belonging to this type. The sides 

 which the two median flaps turn towards each other are not sharp edges, as would 

 appear to be the case when viewed from beneath. The two edges are, in fact, 

 turned dorsad, so that two narrow longitudinal surfaces are formed, which constitute 

 the right and left walls of the channel situated between the two median flaps. In 

 this channel the genital opening is situated. 



The division into six sclerites is repeated to some extent in the eighth sternite. 

 The homology of these will be most apparent if the central portions be discussed 

 first and the more peripheral portions later. Above the admedian sclerites of the 

 seventh sternite, and showing through them in a ventral view, are two strongly 

 chitinised rods which appear to terminate distally as such, but in reality each is 

 continued by the inner edge of a small membraneous lobe C (text-fig. 9). These 

 lobes are connected with the eighth sternite and correspond to the median flaps of 

 the seventh sternite, there being a pair of them, as is also the case with that 

 sternite. These lobes of the eighth sternite do not bear bristles. On each side of 

 the median gap are two square lobes covered with many bristles of the first type. 

 These lobes correspond to the admedian plates of the seventh sternite ; each is, 

 however, completely fused, both proximally and laterally, with the adjoining lateral 

 sclerite of the eighth sternite, which adjoins and is fused with the eightli 

 tergite. The figure here reproduced is taken from a dissection, and consequently 

 the segments are much flattened out, with the result that the central gap in the 

 seventh and eighth sternites is larger than in a state of nature. 



The ninth segment in both sexes is a single chitinised ring bearing hairs of 

 the third type. The tenth segment consists of two feebly chitinised plates between 

 which the anus opens, each plate bearing a row of very minute hairs. 



