An Empusa Disease of Drosophila

Summary

The two fruit-flies Drosophila repleta and melanogaster are attacked by an Entomophthorous fungus identical in all structural characters with Empusa Muscae which attacks the common house-fly Musca domestica. Conidium formation, as observed from stained and sectioned material of the Drosophila flies dead with the disease, is by means of the moving upward of protoplasmic threads and the many nuclei into a sterigma arising as a bud on the top of the conidiophore tube. When the entire content of the conidiophore has flowed into the sterigma causing it to swell up to form a bell-shaped spore, the conidium is cut off from the emptied conidiophore tube by a cross-wall. Resting spores similar to those found in dried house-flies were also found in connection with the fungus attacking the Drosophila species.

I hereby acknowledge my indebtedness to Dr. R. A. Harper for his many valuable suggestions in this study and the preparation of this paper.