The Genera of Eastern North American Chloroperlidae (Plecoptera): Key to Larval Stages

Considerable changes in the systematics of North American chloroperlid stoneflies have resulted from the elevation of subgenera created by Ricker (1943) to generic status by lilies (1966) and Zwick (1973). Most significant are the new combination Rasvena terna, and the division of Alloperla (s. 1.) into five genera, only three of which occur in the region under study. Baumann (1974) separated the closely related species Alloperla imbecilla and A. atlanticum. Harper and Roy (1975) described the male of Utaperla gaspesiana, the first member of the Paraperlinae known from the Northeast, although Ricker (1952) found larvae from Tennessee that were referable to this subfamily. Hitchcock (1974) has summarized the status of members of the family found in Northeastern North America prior to 1971, and has provided species level keys for adults, but has retained the generic classification of Prison (1942). At present, the family Chloroperlidae is represented in Eastern North America by 24 species in two subfamilies and six genera (Table 1). Larval stages are known only from four of these 24 species. This paper provides keys to genera of larvae needed because of nomenclatural changes and description of new species. The larval stages of Suwallia marginata remain unknown. I have examined specimens of the Western North American species Suwallia pallidula. These may be separated from Sweltsa by the relatively fewer setae of the fore and hind femora, and on the eighth tergite, as well as the fewer long setae present on the apical corona of subterminal cereal segments.