On the Larva and Pupa of a Parasitic Phorid Fly—Hypocera incrassata Mg

On Jan. 27th, 1920, among a number of nearly fully grown larvae of Bibiomarci which had been kept in the laboratory about two weeks, a few individuals were observed to be unhealthy or dead. These latter were found to contain parasitic Dipterous larvae, which eventually proved to be those of Hypocera incrassata Mg. Certain of these larvae were observed to be leaving the bodies of other larvae of Bibio marci at the same time.