Consists of two ovaries, two oviducts (Fig. 83, Od), a median vagina (Fig. 83, Vg) and a median spermatheca (Fig. 83, Sta) for reception and storage of spermatozoa (Fig. 77, Sz) Each ovary is made up of from 24 to 26 ovarioles united at their anterior ends in a suspensory ligament (Fig. 83, Sl) There are usually twelve oöcytes in each ovariole which, along with the whole ovary, are covered by a thin structureless membrane, the tunica propria.
The terminal filament (Fig. 83, Sl), an egg tube (Fig. 83, Et), and a supporting stalk or pedicel (Fig. 83, P), as defined by Snodgrass (1935a) are all present in Macropathus filifer.
The terminal filament (Sl) which forms the anterior part of the ovariole is slender and threadlike and consists of a solid strand of cells ensheathed in the tunica propria. The terminal filaments are united together to form the suspensory ligament.
The egg tube (Et), the middle and main portion of the ovariole, contains the germ cells. Each egg tube consists of two parts the anterior end is the end chamber, or germarium (Fig. 83, G), containing germ cells in an active state.
Text-Fig. 17.—Reproductive System Figs. 74-79—Histology of tests showing development of spermatozoa. Fig. 74—Germanium Fig. 75—Spermatogonial cells Fig. 76—Spermatid containing developing sperms. Fig. 77—Spermatid ruptured to release sperms Fig. 78—Sperm bundle Fig. 79—Three sperm bundles grouped together Fig. 80—Dorsal view male reproductive system Fig. 81—Ventral view lower portion of male reproductive system Fig. 82—L.S. follicle of testis Fig. 83—Dorsal view female reproductive system Fig. 84—Mature egg. Fig. 85—Oocyte from posterior end of ovary
Ac, apical cell, Cd, cytoplasm and deutoplasm, Ch, [ unclear: ] , Co, calyx of oviduct, De, ductus ejaculatorius, Dsz, developing spermatozoa En, endapophysis, Es, epithelial sheath, Et, egg tube; F, follicle; Fca, feebly chitinized arch connecting rami G. germanium. Ga, genital aperture H. heads, Lt, left testis, Mr, muscle attached to ramus N nucleus P pedicel, Pn penis, Ps, pseudosternite, Psh, peritoneal sheath, Rps ramus of pseudostermte Rt, right testis, Sc spermatogonia, Sch, chorion sculptured, Sgc spermatogomal cyst, Sgp, subgenital plate, Sl. terminal filaments uniting as the suspensory ligament, St, spermatidia, Stv, spermatheca. Sz spermatozoa, T, tails; Tvs, tubules of vesrculae seminales, V vacuoles, Vd [ unclear: ] deferens, Ve, vas efferens; Vg, vagina, Vm, vitelline membrane, Vs, vesiculae seminales, Vt, vitellarium, Wa white area.
of division and incipient differentiation, and behind this is the zone of growth, or vitellarium (Fig. 83, Vt), the region in which the egg cells grow and attain their mature size. From the germarium are differentiated the oöcytes (Fig. 85) and the follicular epithelium which forms the egg chamber for each oöcyte, and also secretes on its inner surface the egg shell or chorion (Sch) The outer surface of the chorion retains the marks of the cells that produced it in the form of a honeycomb pattern of fine ridges reproducing the outlines of the cells of the follicular wall (Fig. 84). At the upper end of the egg the chorion is incomplete, and this part forms the micropyle of the egg. Since oocytes are produced continuously from [ unclear: ] , the first encysted oocyte becomes the lowermost and the first mature oöcyte in the vitellarium. Thus the region contains a linear series of oocytes gradually increasing in size as they near the oviduct Maturation of the oöcyte does not take place until the egg is laid, even though it is encased in the chorion which is tough, strong and white in colour.
There are two principal types of egg tubes in insects distinguished by the presence or absence of special nutritive cells within the follicular tubes Those with cells specialized to provide nutrition for the ova are meroistic and those without are panoistic. In Macropathus filifer, and most Orthoptera, there are no nutritive cells present and the egg tubes therefore belong to the panoistie type.
The pedicels (Fig. 83, P) of the ovarioles are short ducts connecting the egg tubes with each lateral oviduct (Fig. 83, Od) When the first egg is ready to be laid the wall of the pedicel is dissolved away and the egg passes down into the oviduct The upper part of the oviduct, the egg calyx (Fig. 83, Co), can become greatly dilated and serves as a pouch for storing some of the eggs till they are laid The oviducts are simple muscular tubes without accessory structures of any kind The complete structure of the ovaries may be seen only in an immature female of Macropathus filifer. In a gravid female the most distal eggs have matured and severed the connection of the pedicels to the calyx of the oviduct Most of the eggs lie loose in the body cavity on either side of the hind gut and when required pass to the calyx of the oviduct and from there to the exterior.
The two oviducts unite to form a short median vagina (Fig. 83, Vg) opening on the under surface of the sub-genital plate (Fig. 83, Sgp) which forms the roof of the copulatory chamber The vaginal aperture may be closed by a little flap of tissue attached to the base of the sub-genital plate.
The spermatheca (Fig. 83, Sta) consists of a median blind tube with muscular walls, branching half way along its length into two tubes the longer of which curves over the shorter one. Unlike the spermatheca of most insects, it does not open into the vagina but on to the lower surface of the copulatory chamber. It seems probable that during copulation the flap of tissue at the entrance to the vagina can be pressed over the aperture, closing it so that the spermatozoa, being unable to pass up that way, go to the spermatheca for storage. Fertilization of the egg must take place as it crosses the copulatory chamber and passes the spermathecal aperture, on its way to the valves of the ovipositor and the exterior.