THE FUNCTION OF THE CORPUS ALLATUM IN MUSCOID DIPTERA

Abstract

1. Evidence from extirpation and transplantation experiments suggests that the ring gland of Lucilia sericata and Sarcophaga securifera produces a hormone concerned with normal development. Its action can be seen in the larva where it results in puparium formation, and in the adult fly first in the changes which occur during the breakdown of the larval fat body cells and subsequently in the changes undergone by the adult fat body cells, the oenocytes, and the development of the ovaries. 2. These last two activities may be under the influence of a hormone (probably different from that influencing development), whose action seems to be on the general metabolic activity of the fly. The oenocytes undergo marked changes after extirpation of the ring gland. If these are concerned with some general metabolic function, as seems likely, the action may be primarily on them and the effects on fat body cells may be altered by implanting a ring gland into the abdomen of a fly, after extirpation of the ring gland, but this has no visible effect on oenocytes or on ovarian development. 3. Castration of adult female Lucilia sericata results in hypertrophy of the cells of the corpus allatum. No effect is produced in the male Lucilia sericata or in either sex in Sarcophaga securifera. 4. Destruction of the innervation of the ring gland of Sarcophaga securifera results in slight hypertrophy of the corpus allatum cells, and of their nuclei. The physiological significance of this hypertrophy is not yet known.