March, 1920.] Sharp : Studiks IX Rhyxchopiiora. 77 



ratus, except the short muscular ductus ejaculatorius. (Imms., 

 Trans. R. Soc. London, B, No. 361, 1919.) It is a long step from 

 this simple condition to the state we find in the Riiyncophora, and 

 yet during- the evolution of this complex condition a successful cor- 

 relation is maintained between the male and female structures, and 

 this in spite of their ever-increasing divergence. It would appear 

 at first sight that it would have been better to retain the original sim- 

 plicity of the sexual structures. 



At present I can see no way to comprehending the great compli- 

 cation of the copulatory structures that prevails in the higher insects, 

 and that perhaps reaches its greatest extent in the Lamellicornia and 

 Rhyncophora in Coleoptera. 



One slight suggestion may be made as to the complexity of func- 

 tion of the female portion of the genital conduit, for its most impor- 

 tant function is the transmission of the egg to a suitable position for 

 its successful development ; and it has also to receive the sperm from 

 the male, to preserve it in a special receptacle, and also to fertilize 

 each egg before its extrusion. 



For each of these purposes special structures exist ; but at present 

 we know very little about the functions. Especially obscure is the 

 process of fertilizing the egg. The spermatozoon has to pass along 

 the duct from the spermatheca which is sometimes of extraordinary 

 length, much longer than in Conofracheliis hrevisctis, while in other 

 cases it is quite short. The function of the bursa is also obscure. 



We now know that in some species of Rhyncophora males are 

 not known to exist though females are abundant; hence partheno- 

 genesis undoubtedly occurs, and it is clear that in the history of the 

 species the female is more important than the males, and it seems 

 probable that in the evolution of the structures under consideration 

 the female has led the way, and the male structures have developed 

 in correlation with the changes in the female. But as to how this 

 necessary correlation has been brought about I am unable to offer 

 any suggestion of real importance. 



If this paper has any value it is chiefly due to Mr. and Mrs. F. 

 Muir of Honolulu, who made the drawings and took considerable 

 pains to ascertain difficult points of the anatomy. 



