Growth and development of flesh flies as influenced by the feeding of hypophysis (Pituitary gland).

1. Flesh fly larvae of the speciesSarcophaga saracena andCalliphora erythrocephala were used. Different groups of larvae from the same parent, the same litter and under approximately the same meteorological conditions were fed exclusively on an abundant diet of the anterior lobe, posterior lobe and whole gland of the hypophysis of the pig. The controls were fed on an abundant diet of brain and muscle, obtained from the same animal. 2. A method for obtaining quickly the first stage larvae of a larviparous fly by cesarotomy was developed. 3. When fed to flesh fly larvae under the conditions described, anterior lobe of the hypophysis exercises no growth promoting influence; neither was the rate of metamorphosis accelerated over that of the control animals. 4. The differences in growth that do occur may be conveniently accounted for by the normal variation in growth development occurring in the species. 5. No toxic effect or any observable retardation of growth was produced on the larvae as a result of an exclusive and abundant diet of the gland substance. 6. The larvae ingesting muscle showed an increased larval period ranging from 25 to 40 hours over that of the maggots feeding on the other substances and this factor is dependent on a slower rate of liquefaction of this tissue, for the pupal period in all groups of larvae of the same parentage was approximately of the same duration. 7. The chemical make up of the different substances fed, as well as any resulting bacterial action on them does not appear to be of any great significance in these experiments, since the larvae feeding on them developed into healthy adult flies. 8. Since the injection of extracts of hypophysis (anterior lobe) is usually effective and in most cases non-effective when the gland substance is fed by mouth, it becomes necessary to make a distinction between the effects produced by the feeding of the hypophysis and those resulting from the injection of its extracts.