THE VAGINA AND UTERUS 507 



change which is undergone by the cuticula of the insect itself immediately after 

 ecdysis." (Wheeler.) 



The vagina or uterus. - - This is simply the end of the common 

 oviduct, which, when dilated, is called the vagina, and, in the pupi- 

 parous forms, the uterus. 



In the cockroach the vagina opens by a median vertical slit 

 situated in the 8th sternite, into the genital pouch or bursa, upon 

 the dorsal wall of which the orifice of the spermatneca is situated. 

 In the sheep-tick the oviduct is enlarged to form the so-called 

 uterus, which furnishes a milk-like secretion for the nourishment 

 of the larva during its intra-uterine life. 



In insects in general, the external opening of the vagina is simple, 

 the chitinous structures (valves) at the opening being adapted to 

 receive the male intromittent organ. 



When the eggs are to be deposited deep below the surface of the 

 earth, or in wood, or in wood-boring larvae, or in the body of cater- 

 pillars, etc., they are inserted by the ovipositor (see p. 167). 



Signs of copulation in insects. Leydig has collected, partly from his own 

 observations and partly from those of others, a number of cases in which female 

 insects bear traces of having had sexual union, in the form of tags or plates 

 attached to the body, and apparently formed from material secreted by the 

 male. Such probably is the "pouch" on the abdomen of Parnassius apollo, 

 and a somewhat similar structure in Fulgora laternaria, and such is the plate 

 which is found on the hinder part of the abdomen of Dyticus latissimus and 

 D. marginalis. Leydig compares these structures with the white plate in 

 Astacusfluviatilis, and with the little white lid on the spider Argenna, and finds 

 analogues among vertebrates. (Arbeit. Zool. Zoot. Inst. Wiirzburg, x, 1891, 

 pp. 37-55, 2 Figs.) 



LITERATURE ON THE ORGANS OF REPRODUCTION 

 a. General 



Hunter, J. Observations of bees. (Phil. Trans. Roy. Soc. London, 1792, Ixxxii, 



pp. 128-195.) 

 Hegetschweiler, J. J. Dissertatio inauguralis zootomica de insectorum genitali- 



bus. Turici, 1820, pp. 28, 1 PI. 

 Audouin, V. Kecherches anatomiques sur la femelle du Drile jaunatre et sur 



le male de cette espece. (Ann. Sc. nat., ii, 1824, pp. 443-462, 1 PI.) 

 Miiller, Johannes. Ueber die Entwickelung der Eier im Eierstock bei den Ge- 



spenstheuschrecken. (Nova Acta Acad. Leop. -Carol., xii, 1825, pp. 555- 



672, 6 Taf.) 

 Dufour, L. Recherches anatomiques sur les Carabiques et sur plusieurs autres 



insectes cole"opteres. Organes de la ge'ne'ration (Ann. Sc. nat., vi, 1825, 



pp. 150-206, 6 Pis.; pp. 427-468, 4 Pis.). 



