Published online by Cambridge University Press: 31 May 2012
Ide (1935) has studied the various instars in the development of the nymph of Ephemera simulans Walker, but does not state the length of the life cycle. Neave (1932) decided that in Lake Winnipeg species of Hexagenia, a genus very closely related to Ephemera, took two years to complete the life history cycle. The length of the life cycle and the rate of development of the species of Ephemera have been discussed but never satisfactorily settled. The present paper attempts to answer these questions with respect to Ephemera simulans in Lake Wawasee.