142 



ENTOMOLOGY 



FIG. 182. 



minates in the intromittent organ, or penis. Often each vas 

 deferens is dilated near its mouth into a seminal vesicle, or 

 reservoir; or there may be only a single seminal vesicle, aris- 

 ing from the common duct. One or more pairs of glands 

 opening into the vasa deferentia or the ductus ejaculatorius 

 secrete a fluid which mixes with the spermatozoa and often- 

 times unites them into packets, known as spermatophores. 



All these parts are subser- 

 vient to the formation, pres- 

 ervation and emission of the 

 spermatozoa. These minute 

 thread-like bodies (Fig. 180) 

 arise in the testicular follicles 

 from a germinal epithelium, 

 and consist, as in vertebrates, 

 of a head, middle-piece and 

 a vibratile tail without en- 

 tering into the finer struc- 

 ture. 



Female Organs. Each 

 ovary (Fig. 181) consists of 

 one or more tubes opening 

 into an oviduct. The two 

 oviducts enter a common 

 duct, the vagina, which 

 opens to the exterior, often 

 through an ovipositor. Fre- 

 quently the vagina is ex- 

 panded as a pouch, or bursa copulatrix, though in Lepidoptera 

 the bursa and the vagina are distinct from each other and open 

 separately (Fig. 182). In most insects a dorsal evagination 

 of the vagina forms a seminal receptacle, or spermatheca, from 

 which spermatozoa emerge to fertilize the eggs. The acces- 

 sory glands, either paired or single, provide a secretion for 

 attaching the eggs to foreign objects, cementing the eggs to- 

 gether, forming an egg-capsule, etc. 



Reproductive system of female Lepi- 

 doptera. b, bursa copulatrix; f, terminal 

 filament; g, cement glands; o, o, ovaries; 

 od, oviduct; r, receptaculum seminis; v, 

 vagina; vs, vestibule, or entrance to 

 bursa. After KOLBE. 



