Observations and Experiments on the Blow‐fly (<i>Calliphora erythrocephala</i>) during the First Day after Emergence.

Abstract

The digging movements of the freshly emerged flies have been described and analysed. Direction of digging is determined by light, but not by gravity. The process of the inflation of the fly with air and the expansion of the wings has been described and analysed. During digging these reactions are inhibited and postponed. Air-pumping occurs apparently independently from external and internal stimuli; it starts automatically a certain time after emergence and stops automatically after a certain period. It has been experimentally proved that the first filling of the air-sacs is due to negative pressure in the body arising from the diffusion of air out of the gut (in accordance with a hypothesis of Evans). Colouring and hardening of the skin are inhibited and postponed during prolonged digging.