664 THE GENERATIVE ORGANS. 



female within the cloacal pouch or ovipositor, or are introduced 

 into the orifice of the utero-vaginal tube. 



In the Cockroach there is no vestige of a penis, and the 

 right and left gonapophyses are unsymmetrical. The left 

 gonapophysis is provided with a long movable hook, but the 

 right one contains a cavity protected by a spring lid, which 

 closely resembles the organ on the palpus of male spiders. I 

 have little doubt it serves to contain a large spermatophore, 

 which is transferred by the hook to the cloacal pouch of the 

 female. Cornelius,* who gives a description of the sexual act 

 in this insect, describes it as being accomplished with great 

 rapidity, and it is highly improbable that the sperm could be 

 transferred directly from the short wide vas deferens of the 

 male to the oviduct or receptaculurn of the female. The 

 probability that a large spermatophore is simply transferred to 

 the cloacal pouch of the female is rendered greater by the fact 

 that such is very generally the nature of the act of copulation 

 in the Orthoptera. 



The Vas Deferens varies greatly in length in different insects ; 

 it is sometimes wide and short, as in the Cockroach, some- 

 times long, narrow and much convoluted. In the Blow-fly it 

 is i'5 mm. in length, and is thickest at its commencement, 

 where it has a diameter of '2 mm., tapering gradually towards 

 its termination, where its diameter is about 'i mm. It has the 

 same structure as the paragonia and vasa efferentia. It termi- 

 nates in the ejaculatory sac. 



Segmental Ducts. The vasa efferentia, paragonia and vas 

 deferens are apparently morphologically related to segmental 

 tubes. I shall, however, return to this subject. They are 

 constantly present, and so offer a marked contrast to the 

 remainder of the genital tube, the ejaculatory sac and duct, 

 which I regard as the ' secondary duct.' This is developed 

 from the hypodermis, and is frequently entirely wanting, as is 

 apparently always the case \\hrii there is no intromittent penis, 

 or when this organ is replaced by a pair of more or less complex 

 gonapophyses. 



rage zur nahern Kenntniss der Periplaneta orientalis.' KlbcrfclJ. 1853. 



