Although students and investigators at the Douglas Lake Biological Station frequently encounter the peculiar transparent larvae of the "phantom midges" (Chaoborus spp. = Corethra spp. of authors), no intensive study has yet been made of the species occurring in this region. These larvae ordinarily remain in the deep-water sediments of lakes during the day; at night they migrate upward into the open water, often reaching the surface. They are predaceous on zooplankton. Because they are prominent members of the lacustrine community and have long been of interest to limnologists and fisheries biologists, it appears worthwhile to record what has been learned of the occurrence of the local species and to present a key for identification of their larvae based on Cook’s 1956 monograph. The following notes are based on collections of Chaoborus larvae, pupae, and adults made in the vicinity of the UMBS in Cheboygan and Emmet counties, Michigan, mostly during the summer of 1965. 30 collections were made from 14 localities. All specimens were preserved in Kahle’s fluid and are in my collection. Figs. 1-16 were drawn from local specimens, using a compound microscope equipped with an ocular grid.