411 



clu 



Supragenital plates are absent in the male of Arixetiia, and 

 the sclerites usually present in both sexes of Dermaptera between 

 the tenth tergite and the base of the callipers on the one hand, 

 and the anus on the other, are but feebly developed. There are 

 two of them on 

 each side of the 

 body. One is a 

 mere membranous 

 fold, lying at the 

 base of the calliper 

 and being a little 

 more strongly 

 chitinised only 

 near the supra- 

 anal plate (tergite 

 13). This is pre- 

 sumably the coxo- 

 podite of the 

 calliper. The 

 other sclerite is 

 larger and hairy, 

 representing the 

 tenth sternite 

 (text-fig. 23, St. 

 10). The anus is 

 flanked by a mem- 

 branous swelling 

 on each side, a 

 third and fourth 

 swelling being placed in front of and brliind ihv anus, the 

 former pair bearing a few minute hairs (text-fig. 23). 



In the female the sclerite which we regard as the coxupodite 

 of the calliper is yet more indistinct than in the male, and 

 the tenth sternite is so much fused with the tenth tergite that 

 the suture has almost disappeared proximally. In both sexes the 

 inner portion of the tenth sternite is membranous, while the 

 apex is more strongly chitinised in the female than in the male. 



The seventh sternite is, as in other Dermaptera. the hirgest 

 of all, and lia> the apical margin visibly emarginate. Dorsally 



cod 



Fig. 23. — Tail-end of Arixenia jacobsoni Ç 

 tral view, py, pygidium ; mpy, metapygidium 

 tclson {= tergite 13); tg.^, tg.«, tg.», tg.w 

 gites 7 to :o ; st.'', st.*, st.*", sternites 7, 8, and 10 ; 

 an, anus ; clu, clutch ; o.rs, orifice of rcceptaculum 

 seminis ; cod, orifice of oviduct. 



ven- 

 téis, 

 ter- 



