200 ANATOMY. 



II. OF THE MALE ORGANS OP GENERATION. 



146. 



WE have already indicated that the male sexual organs consist 

 essentially of the same parts as those of the female. They also are 

 divided into interior and exterior ; the former of which comprise the 



TESTES, VASA DEFERENT/A, VESICA SEMINALIS, and DUCTUS EJA- 



CULATORIUS SEMINIS ; and the latter, the PENIS and the PREHENSILE 

 ORGAN connected with it, and placed at the sexual orifice. We will 

 therefore now proceed to the consideration of the internal male organs 

 of generation. 



A. INTERNAL ORGANS OF GENERATION. 

 147- 



THE TESTES. 



The TESTES are glandular white bodies generally present in pairs, and 

 which secrete the spermatic fluid. They regulate themselves in form 

 and structure according to the differences presented by the glandular 

 organs in insects in general, so that the majority are long convoluted 

 vessels; some take the form of fasciculi of blind filaments, and a few 

 lastly appear as round glandular bags. Their structure is regulated by 

 their exterior appearance. Vascular testes have, like all the glands 

 of insects, two tunics ; the internal loose mucous one displaying a 

 parenchymatous appearance, the exterior one smooth, but coarser in 

 structure, and corresponding with the exterior muscular membrane of 

 all internal organs. Round testes have likewise a smooth coating, 

 which enclose a multitude of small vesicular bags in the cavities of 

 which the sperm is secreted. 



As the testes are analogous to the female ovaries, we should conceive 

 that they as well as the latter should stand in connection with the 

 dorsal vessel ; but this has not yet been detected, although many forms 

 of testes extend in delicate filaments upwards which may apparently 

 be the indication of such a communicating thread, as is the case in the 

 ovaries. The analogous importance of both organs, which is most strongly 

 proved by the progressive metamorphoses of insects, to which we shall 

 subsequently return, is evinced also by the situation of the testes in the 



