The Function of the Halteres of Flies (Diptera)

Abstract

SUMMARY. In agreement with nearly all the older authors, and in disagreement with v. Buddenbrock, the disturbance of flight after removal of the halteres in flies consists of a loss of equilibrium. The effects of the removal of the halteres are almost eliminated by fixing a piece of cotton to the tip of the abdomen. This stabilizes the flight and largely compensates for the loss of equilibrium otherwise incurred. v. Buddenbrock's conception of a purely stimulatory function for the halteres cannot be maintained; the loss in irritability and spontaneity produced in flies by removing the halteres is largely a shock effect. The halteres vibrate during walking. No explanation for this phenomenon has been so far found. In the Drosophila mutant “vestigial” reduction of wings and halteres runs parallel. In the mutant “bithorax” the increase in size of the halteres is accompanied by a complete loss of their function, so that flight of the intact “bithorax” is of the same unbalanced type as of the normal wild Drosophila without halteres. Generally in Diptera reduction of wings and halteres runs parallel. In co‐operation with Dr. J. W. S. Pringle a new theory of the function of the halteres has been advanced which regards the halteres as equilibrium organs functioning by the gyroscopic action of the vibrating haltere on the sense‐organs in the base of the haltere.