Aquatic biologists have long been familiar with the beautiful and interesting larvae of Chaoborus which are found in most of our lakes. Their peculiar habit of migrating daily krom the bottom of the lake to the surface and back again is well known. The data reported here are concerned not so much with this interesting habit but rather with the general ecology of the species.

The feeding habits of certain leafhoppers (Cicadellidae) are of particular importance, not only because of the diverse nature of the injury produced by different species, but primarily because a number of species are vectors of some very destructive plant viruses. An investigation of the feeding habits of certain species was undertaken to learn the nature of the injury within the host plant, especially the particular tissues fed upon and their relation to the external symptoms, and to bring out any features of the methods of feeding which might bear some relation to the transmission of viruses.