734 THE C, !:. \l-.R ATI \'E ORGANS. 



without dcubt with the progenital somite, and represent the 

 anterior gonapophyses of the male. 



The manner in which the ventral portion of the genital 

 somites is drawn forwards during development, so that the six 

 papilla,- all appear to arise from the same place, renders it 

 exceedingly difficult to trace the development of the individual 

 elements of the ovipositor, or sting, and gives rise to the decep- 

 tive appearance as to the relation of the bases of the parts, as 

 those belonging to the posterior somites are frequently drawn 

 further forwards than those arising from the anterior somite. 

 The only certain criterion as to their nature is the position of 

 the orifice of the sexual duct. 



The difficulty of accounting for the passage of the ova 

 through the sting in the aculeate Hymenoptera, and through 

 the narrow channel in the Terebrantia, has led to the view 

 that the sexual duct opens either behind or in front of the 

 sting. It certainly opens through the terebra, and I have 

 sought in vain for any other opening of the generative duct in the 

 aculeate Hymenoptera. -In these Insects I suspect that the 

 parts of the sting, or terebra, are separated during oviposition, 

 although it is exceedingly difficult to understand how this 

 occurs, as the parts are closely locked together when used as a 

 borer or sting. The anatomy of the parts renders it certain 

 that such a separation is effected in the Bees just as it is in the 

 parasitic Hymenoptera, in which there can be no doubt the 

 passage of the ova is through the terebra. The ova in the 

 aculeate Hymenoptera do not, perhaps, pass through the whole 

 length of the sting, but only through its base ; but the oviduct 

 < i i tainly neither opens in front of nor behind the base of the 

 sting, but through its cavity. Knipelin held that the external 

 "ritice of the oviduct is in front of the base of the sting, and even 

 if this is the case, homology indicates that the latter is developed 

 from the nirsngeriital, and not from the progi-nital, somite. If 

 such an orifice exist, I cannot understand how I can have 

 failed tn ili.-i-iivcr it. 



The Penis. --It is well known that the efferent ducts of the 

 gon;ids in the Crustacea are paired, and situated in the basi- 



