ANATOMY AND PHYSIOLOGY 115 



Ovaries and testes arise from indifferent cells, or primitive germ cells, 

 which are at first exactly alike in the two sexes. In the female, certain 

 of these cells form ova and others form a follicle around each ovum (Fig. 

 185). In the male, the primary germ cells form cells termed spermato- 

 gonia; each of these forms a spermatocyte, and this gives rise to lour sper- 

 matozoa. 



Hermaphroditism. The phenomenon of hermaphroditism, or the 

 combination of male and female characters in the same individual, occurs 



re--- 



FIG. 182. Reproductive system of queen 

 honey bee. a, accessory sac of vagina; b, 

 bulb of stinging apparatus; c, colleterial, or 

 cement, gland; 0, ovary; .od, oviduct; p, 

 poison glands; pr, poison reservoir; r, re- 

 ceptaculum seminis; re, rectum; v, vagina. 

 After LEUCKART. 



FIG. 183. Reproductive system of [fe- 

 male Lepidoptera. 6, bursa copulatrix; /, 

 terminal filament; g, cement glands; o, o, 

 ovaries; od, oviduct; r, receptaculum seminis; 

 , vagina; vs, vestibule, or entrance to bursa. 

 After KOLBE. 



only as an extremely rare abnormality among insects. Speyer estimated 

 that in Lepidoptera only one individual in thirty thousand is hermaphro- 

 ditic. Bertkau (1889) listed 335 hermaphroditic arthropods, of which 8 

 were crustaceans, 2 spiders, 2 Orthoptera, 8 Diptera, 9 Coleoptera, 51 

 Hymenoptera and 255 Lepidoptera. The large proportion of Lepidoptera 

 is due in great measure to the fact that they are collected oftener than 

 other insects (excepting possibly Coleoptera) and that sexual dimorph- 

 ism is so prevalent in the order that hermaphrodites are easily recognized. 

 The most common kind of hermaphroditism is that in which one side 

 is male and the other female, as in Fig. 186. Bertkau found this right- 



