Fig. 103.—The Tenth Tergum reflected to show the external male organs in situ. T10, tenth tergum; p, podical plates; A-F, as in fig. 102; S, sub-anal styles. × 8.
The “titillator” (Brunner von Wattenwyl) is a solid curved hook with a hollow base. Besides these, are several odd-shaped, unsymmetrical pieces (fig. 102, C, D, E, F), moved by special muscles. A pair of styles (see figs. [32]–3 and 103) project from the hinder edge of the 9th sternum. These paired and unpaired appendages are believed to open the genital pouch of the female, but we do not understand their action in detail.[173]
Brehm observes that the male reproductive organs of the Cockroach are most nearly paralleled by those of the Mantidæ. A free penis occurs in all Orthoptera, except Acridiidæ and Phasmidæ.
The male organs of the House Cricket will be found much easier to understand than those of the Cockroach. The testes are of irregular, oval figure, the vasa deferentia very long, tortuous, and enlarged towards the middle of their length. The vesiculæ seminales bear many utriculi majores et breviores. The penis is of simple form, and dilated at the end. The titillator is broad, but produced into a slender prong, which projects beyond the penis. A pair of subanal styles is found, but the unpaired hooklets are wanting or very inconspicuous.
Very little is known about the act of copulation among Cockroaches, and the opportunities of observation are few. The following account is given by Cornelius (loc. cit., p. 22):—
“The male and female Cockroaches associate in pairs, the females being generally quiet. The male, on the contrary, bustles about the female, runs round her, trailing his extended abdomen on the ground, and now and then raises his wings. If the female moves away, the male stops the road. At last, when the female has become perfectly still, the male goes in front of her, brings the end of his abdomen towards her, then moves backwards, and pushes his whole length under the female. The operation is so rapid that it is impossible to give an exact account of the circumstances. Then the male creeps out from beneath the female, raises high both pairs of wings, depresses them again, and goes off, while the female usually remains quiet for some time.”