20 



INTRODUCTION. 



and more differentiated type, but this is open to question. The 

 other important female organs of reproduction are the vagina 

 leading to the eopulatory pouch and the spermatheca or recepta- 

 culuin seminis. 



In the male the chief internal organs which answer to the 

 ovaries of the females are the testes, the secretion from which is 

 conveyed by the vasa deferentia into the vesiculse seminales. The 

 two testes may consist of simple coiled tubes or of a number of 

 follicles opening into a common tube ; these are often contained 

 in a capsule. In the Adephaga the tubular structure is found, 

 whereas in the rest of the Goleoptera they appear to be follicular ;. 



Fig. 13. — Keproductive organs of a male bark-beetle, ho, testicle ; si, vas 

 deferens ; bl, seminal vessel ; og, ductus ejaculatorius ; dr, accessory 

 gland. (After Graber.) 



it must, however, be admitted that hardly a sufficient number of 

 species have been dissected to justify a very wide generalisation 

 in this respect. The vasa deferentia are fine tubes, varying very 

 much in length (in Dytiscus they are five times, and in Cetonia 

 aurata thirty times as long as the body), and they are furnished 



s d.eoc. 



d.eTL. f; 



Fig. 14. — iEdeagus of Philonthus nigritulus, $ . d.en., duct entrance; 

 d.ex., duct exit ; s, sac ; /, furca ; a, appendage. (Original from drawing 

 by Sharp.) 



with accessory glands, consisting of tubes, the secretions of which 

 mix directly with the semen. The majority of Goleoptera possess 

 one pair, but several pairs are present in some families (e. g.,, 

 Hydeophilid^e and ElateriDje). Several of these points will be 



