320 ERNEST WAimEN. 



The sternite of abdominal segment IX is a curved plate- 

 quite similar in character to the tergite below. 



Abdominal segment X, telescoped into segment IX, bears a 

 sternite consisting of a right and left setose plate. The two 

 plates are close together on the upper surface in the female 

 (fig. 14, S.X.), but in the male they are definitely lateral in 

 position (figs. 11 and 12). 



In the male the homologies of the chitinous structures of 

 abdominal segment X are more obscure than in the female. The 

 two trough-shaped lateral lobes together with the chitinous 

 penis-tube can be everted far forwards. Associated with 

 this apparatus the main chitinous parts are: (1) Two 

 laterally placed setose plates, and (2) two U-shaped bars of 

 chitin supporting and strengthening the lateral lobes or 

 paramera (fig, 10, T.X). From the relative position of these 

 chitinous pieces it Avould seem probable that the former 

 represent sternite X and the latter tergite X, but Tragardh 

 regards the latter as sternite in Termitomimus. 



2. Internal Anatomy. 



Cuticle. — The cuticle tends to be of a more or less uniform 

 thickness all over the body, but its density varies greatly. 

 In the white or translucent portions of the body the cuticle is 

 mostly as thick as elsewhere, but it is highly flexible and soft, 

 and in certain places it is doubtless permeable to gases and 

 probably even fluids. In most places the cuticle is seen to 

 consist of two layers — an epistracum and an endostracum. 



The external yellowish-brown areas which look like isolated 

 plates of chitin in the whole specimen are, curiously enough, 

 scarcely distinguishable in ordinary stained sections. The 

 reason is this : the yellow chitinous plates (text-fig. 3, pr. .st., 

 ms. St., mt. st.) are quite continuous with the general cuticle 

 {g. cii.) covering the body, and they are usually no thicker 

 than the cuticle ; they only differ from it in being denser and 

 more homogeneous, and in being coloured bright yellow. In 

 sections stained with orange the distinction between the 

 plates and the surrounding cuticle becomes altogether obscure. 



