Male generative organs of the Hive Bee (Apis mellifica): a, testes; b b, vasa deferentia.

Fig. 168. Male generative organs of the Hive Bee (Apis mellifica): a, testes; b b, vasa deferentia; cc, seminal receptacles; d, auxiliary glands; e, common excretory duct; f, g, ejaculatory sacculus.

(881). In the female of Meloloniha the ovaria are long tubes, forming two distinct fasciculi symmetrically situated on the two sides of the body. At their commencement (fig. 169, uu) the ovigerous tubes are slender, and the ova which they contain at this point are in a very rudimentary state of development; they generally dilate, however (ttt); and as they expand, the ova are seen to attain larger dimensions. Near its termination, each ovarian tube assumes a granulated texture (ss); and they all ultimately open into the corresponding excretory canal (r r).

(882). All the ovarian tubes of one side are united into a bundle, by a ligament (yx) which Joh. Muller * traced to the dorsal vessel, and believed to be a vascular canal adapted to bring blood immediately into the tubes wherein the ova are formed; but no satisfactory evidence has been adduced in proof of the existence of such an extraordinary communication, and the thread in question is most probably a mere ligamentous connexion.

(883). Taking the higher animals as a standard of comparison, we may suppose the formation of the eggs in these tubes to be accomplished in the following manner: - In the upper part of the tube (u) is formed the yelk, enclosed in its peculiar membrane, and provided with that wonderful germ from which, after impregnation, the future being is to be developed; as the yelk slowly descends to the more dilated parts of the canal (t t), it becomes clothed with the albumen which constitutes the white of the egg, and ultimately, before quitting the nidus of its formation, receives from the granular termination of the ovary its last integument or shell. Thus completed, it passes into the excretory canal (r r); and this, meeting the corresponding tube derived from the ovaries of the opposite side, joins it to form the common oviduct (I), through which the egg is conducted out of the body.

Female generative organs of the Cockchafer (Meloloniha vulgaris.)

Fig. 169. Female generative organs of the Cockchafer (Meloloniha vulgaris): 'ss,tt,uu, ovigerous tubes; y x, their ligamentous origin; rr, excretory canals; I, common oviduct; pp, gluten-secretors; n o, spermatheca.

* Nova Acta Phys.-Med. Nat. Cur. vol. xii. pt. 2.

(884). But we must now advert to certain appendages connected with the common oviduct. These are of two kinds, the gluten-secretors and the sperrnatheca.

(885). The gluten-secretors (fig. 169, pp) are glandular caeca opening into the common egg-canal, and are apparently destined to furnish a glutinous fluid with which the eggs become invested before they are expelled from the body; and thus they are frequently united into long chains and variously-shaped masses, or else the adhesive varnish thus secreted serves to glue the ova to situations favourable to the development of the embryo.

(886). The other organ, or sperrnatheca (fig. 169, n o), has a widely different office, being a receptacle provided to receive the seminal secretion of the male during copulation: it is always situated upon the upper aspect of the oviduct, into which it opens by a small orifice surrounded by a thickened margin or sphincter embracing the neck of the bag, and so disposed as either to retain the enclosed fluid, or to allow it to escape into the oviduct. That this organ really does receive and retain the seminal liquor is proved by the presence of seminal animalcules in its contents; but the matter has been placed beyond a doubt by the experiment of John Hunter*, who actually succeeded in fecundating the eggs of an unimpregnated female by applying to them a little of the fluid contained in its cavity: but that the reader may comprehend fully the reason of such an arrangement, it is necessary to consider the circumstances under which insects propagate.

(887). In most animals, sexual union may be repeated several times during the life of individuals; but in insects intercourse between the sexes is permitted to take place once only; and this solitary congress must suffice for the impregnation of all the ova, however numerous, and however imperfect may be the development of some of them at the time when the embrace occurs.

(888). Let us take the Hive-bee as an example: in the females of this insect the ovigerous tubes (fig. 170, a a) are excessively numerous, and the eggs produced in them may amount to between 20,000 and 30,000. These eggs, of course, arrive at maturity in succession, and not all at once; so that, at the moment when the queen-bee meets her selected mate, perhaps the majority of the ova are not in a sufficiently mature condition to be rendered fertile. Nevertheless the meeting of the sexes cannot be repeated; for no sooner has copulation taken place than the favoured male dies, and, by a simultaneous butchery, all the other males, or drones as they are commonly designated, are destroyed by the working inhabitants of the hive. The quantity of the fecundating liquor, therefore, supplied by one connexion must serve to fertilize all the eggs produced during the lifetime of the queen-bee; and for this purpose it is stored up in the spermatheca (fig. 170, c); so that, how numerous soever may be the eggs formed, they are all vivified as they pass out through the oviducts (b, e), and thus come in contact with the orifice of the reservoir of semen.

* Home's Lectures on Comp. Anat. vol. iii. p. 370.

(889). In Melo'e variegatus (fig. 164) the ovaria (d) consist of wide and capacious sacs, covered externally with innumerable glandiform vesicles, opening into the cavity of the ovary (e.) The gluten-secretor (h) and the spermatheca (g) are seen, as in Meloloniha, appended to the common oviduct (f); but the spermatheca has a small accessory vesicle (i) connected with it, not found in the former examples.