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Most oosorption in the dung beetle Euoniticellus intermedius takes place in the haemocoele, oocytes being extruded from the ovariole before the deposition of the chorion. Oosorption can be induced in the laboratory both by prevention of oviposition and by starvation. For up to two days after the onset of starvation the terminal oocyte appears normal. After three days the prechorionic oocyte may move through the ovariole wall; the yolk spheres are then disrupted. On the fourth day little yolk remains in the extruded oocyte, and most of the extruded cells are degenerating. We suggest that extra-ovariolar egg resorption may be a mechanism for ensuring that the single ovariole is not occluded when conditions are suitable for oviposition.

The female firebrat must mate before she can complete the terminal stages of vitellogenesis. Mating is followed by an increase in stainability of the median neurosecretory cells, and by increased rates of RNA and protein synthesis in these cells. The volume of the corpus allatum, corrected for differences in size among firebrats, increases approximately 70 per cent after mating due to an increase in cell number and to increase in the volumes of both nucleus and cytoplasm. Increased RNA and protein synthesis accompanies these changes in volume. Extirpation of the corpora allata, and the implantation of corpora allata from Periplaneta americana , confirm that these glands stimulate yolk deposition. The results also indicate that the corpora allata can regenerate, and that wounding, or premature initiation of the moulting cycle associated with it, can inhibit vitellogenesis.

Ovarian changes which accompany the changes in the rate of oviposition in founding females of Hodotermes mossambicus involve alterations in the number of ovarioles in which yolk deposition occurs, and in the proportion of oocytes which enter the final stage of maturation.

Under optimal conditions, reproduction does not affect the rate of growth in female Lepisodes. In unmated male and female firebrats, an increase of weight after ecdysis is associated with a single phase of feeding activity, which terminates near the middle of the instar, coincident with the reconstruction of the midgut epithelium. In mated females, a greater increase in weight accompanies a more intense first phase of feeding, and at oviposition a short second phase of feeding commences. The weight of food consumed in this second phase is closely correlated with the weight of eggs laid, and evidently compensates for loss of reserves at oviposition.