INTERNAL GENERATIVE ORGANS OF THE MALE. 663 



utriculi majores and utriculi breviores. The former are milk 

 white and surround the latter, which are more or less trans- 

 lucent. Sections through this organ show that the utriculi 

 majores are precisely similar to the paragonia of other insects, 

 whilst the utriculi breviores differ in no way from the glands 

 which are recognised as the testicle in the majority of insects : 

 they contain sperm-cells and sperm in all stages of develop- 

 ment. The vas deferens divides into two main branches at its 

 anterior end, and each of these terminates in a number of both 

 kinds of utriculi so that, except in the nature of their con- 

 tents, the utriculi majores and breviores are apparently iden- 

 tical and are morphologically similar. 



Rajewsky [328], in 1875, published a paper in Russian, in 

 which he describes what he regards as the true testes, and he con- 

 siders the whole of the utricules of the mushroom-shaped body 

 as vesiculse seminales. The testes described by Rajewsky un- 

 doubtedly exist in the immature male, and are present in the 

 adult male in an exceedingly atrophied condition, so that it has 

 been concluded that the testes undergo atrophy in the adult 

 male. It has been supposed that the mother cells of the sper- 

 matozoa are formed in the glands which Rajewsky regards as 

 testes, and descend into the utriculi, where they undergo 

 further development. If this were really the case it is re- 

 markable that no sperm-cells are ever found in the utriculi 

 majores, and it seems to me that the supposition is exceed- 

 ingly improbable. On the other hand, it may be that the 

 glands of Rajewsky are really the more anterior follicles of 

 a testis, and this more especially as they are persistent in 

 Blatta Germanica, and are functionally active in the adult 

 insect. 



Functions of the Paragonia. The secretion of these glands 

 coagulates with great rapidity in the ejaculatory duct, or in the 

 vagina of the female insect, and is apparently concerned in the 

 formation of spermatophores. In the Orthoptera, in which 

 paragonia are very largely developed, the spermatophores are 

 usually of large size, and only one or two are discharged, and 

 either attached to the exterior of the sexual orifice of the 



