New Larval Descriptions and Comparisons of North American \u3ci\u3eChoroterpes\u3c/i\u3e (Ephemeroptera: Leptophlebiidae)

Formal descriptions of larvae of the western North American species Choroterpes albiannulata and the eastern North American species Choroterpes fusca (Ephemeroptera: Leptophlebiidae) are given for the first time. Specimens, including reared adult and larval associations, of C. albiannulata were available from Nevada, Oregon, and Idaho, and rearings of C. fusca were made from the Huron Mountains in the Upper Peninsula of Michigan. Six of the nine species of North American Choroterpes (subgenus Choroterpes) are now known as larvae. Larval characteristics are compared, particularly with regard to similarities and differences between C. albiannulata and C. fusca, c. albiannulata and the western C. inornata. and C. fusca and the eastern C. basalis. Choroterpes albiannulata is distinct but shares gill morphology with C. inornata. Choroterpes fusca is quite similar to C. basalis, sharing . morphology and color patterning, but with some apparent differences that may prove to be consistent. Certain Choroterpes larvae from Arkansas are probably C. oklahomae (known only as adults from Oklahoma) but cannot be associated at this time. Distributions of species of subgenus Choroterpes are updated, and a revision of the entire genus based on cladistic analysis is recommended