A Key to Species of Cyclops in Iowa

The genus Cyclops is one of the most common of the m1crocrustacea, and it occurs in almost every body of fresh water. Apparently because of this universality it has developed a wide variety of species and forms which are very difficult to distinguish from each other. For any study of ecological or geographical distribution of the genus, specimens must be identified as to species and subspecies. As an aid to such studies the following key has been compiled. This is not a field key in the sense that it can be used for field identification, but it will serve for identification without dissection of the animal, for the common species known to occur in Iowa