Male Reproductive Organs 8i 



sternite. They are rounded chambers beset with 

 numerous tubes {utricles), some of which, opening into 

 the sides and hinder parts of the vesicles, are longer 

 and larger than others which open into their forward 

 central region. The two vesicles join to form a 

 common sperm duct {ductus ejaculatorius) with muscular 

 walls and chitinous lining, which is swollen at its 

 forward end where the vesicles are, contracted in its 



Fig. 56. — Hinder-end of abdomen of Male Cockroach with reproductive organs. 

 T s. testis; D E. ductus ejaculatorius; B. penis; A. titillator. Magnified 

 8 times. From Miall & Denny. 



middle region, and swollen again at its hinder end 

 where it opens amid the hard chitinous plates of the 

 genital armature (fig. <^(>). Below the duct, just 

 before its hinder end, is situated an elongate flattened 

 conglobate gland whose function is unknown (l). 



The general plan of the male organs, as just de- 

 scribed for the cockroach, is constant in most insects, 

 though there may be considerable variation in the 



