The ejaculatory duct is about ·15 inch long, and overlies the 6th-9th sterna. It is wide in front, where it receives the paired outlets of the vesiculæ seminales. Further back it narrows, and widens again near to its outlet, which we find to be between the external chitinous parts, and not into the penis, as described by Brehm. The duct possesses a muscular wall for the forcible ejection of its contents, and in accordance with its origin as a folding-in of the outer surface, it is provided with a chitinous lining. In the adult the fore part of the duct may be distended with spermatozoa. [Illustration: Fig. 101.--Vesiculæ Seminales and Ductus Ejaculatorius of Pupa. _VD_, vas deferens. × 28.] The ejaculatory duct is originally double (p. 194), and its internal cavity is still subdivided in the last larval stage or so-called “pupa.” Upon the ventral surface of the ejaculatory duct lies an accessory gland of unknown function; it is “composed of dichotomous, monilated tubes, lined by a columnar epithelium, all bound together by a common investment into a flattened, elongated mass.”[171] The duct of this gland does not enter the penis, as described by Brehm, but opens upon a double hook, which forms part of the external genital armature (fig. 99, 3). It may be convenient to distinguish this as the “conglobate gland.”[172] [171] Huxley, Anat. Invert. Animals, p. 416. [172] The term “accessory gland,” used by Huxley and others, is already appropriated to glands which we believe to be represented by the utricles of the Cockroach, and which have only a general correspondence with the gland in question. The external reproductive organs of the male Cockroach are concealed within the 9th sternum. The so-called penis (fig. 102) is long, slender, and dilated at the end. It is not perforated, and we do not understand its use, though it probably conveys the semen. [Illustration: Fig. 102.--External Male Organs, separated. The lettering agrees with Brehm’s figures. _A_, titillator; _B_, penis; _C-F_, hooks and plates. × 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] [173] Similar organs, forming a male genital armature, have been described in various Insects. See Burmeister, Man. of Entomology, p. 328 (Eng. Transl.); Siebold, Anat. of Invertebrates; Gosse in Linn. Trans., Ser. 2, Vol. II. (1883); Burgess on Milk-weed Butterfly, Ann. Mem. Bost. Soc. Nat. Hist.; &c.