Annals Entomological Society of America [Vol. XV, 



HOMOLOGIES OF THE MALE AND FEMALE ORGANS. 



As already pointed out in Part I, the lateral gonapophyses 

 or dorsal valvulas of the female are prolongations of the coxites 

 of the 9th segment, the styli when present being borne upon 

 their apices; but, except in the Thysanura and many Odonata, 

 sooner or later becoming lost or absorbed during development. 

 The anterior and posterior gonapophyses are homoplastic 

 outgrowths, belonging to the 8th and 9th segments respectively, 

 and, as found in their most primitive conditiofi, in the Thy- 

 sanura, they are borne upon, or near, the inner margins of the 

 corresponding coxites, close to the bases of the latter. 



Fig 



Fig. 2 



Fig. L 

 Fig. 2. 



Nicoletia (Anelpistina) nieinerti Silv., 8th sternum of female. 



(From Berlese, after Silvestri). 

 Machilis polypoda, 8th and 9th sterna of male. 



(From Berlese, after Silvestri). 



In the Machiloidea and Lepismoidea the coxites of segment 

 9 are similar in the two sexes and the sternite has practically 

 disappeared, except in a few Lepismids, such as Nicoletia, in 

 which there is a well developed sternite in the female only 

 (Escherich, '05), (Text fig. 1). The posterior gonapophyses are 

 represented by the parameres, which are best developed in the 

 Machiloidea and such Lepismoidea as Nicoletia and Atelura 

 (Escherich, 1. c.) As a rule no structures corresponding to 

 the anterior gonapophyses are present in the male, but Silvestri 

 (nee Berlese, '06) shows clearly in a figure of the male of Machilis 



