Marlatt’s “Brood XV” is not currently recognized as a brood of 17-year cicadas. Reports of this brood may represent repeated straggling, or “shadow brooding” from Brood II.
This brood was not recognized by Simon (1988). Blue symbols are from Marlatt (1923).
Marlatt, C. L. 1923. The Periodical Cicada. United States Department of Agriculture, Bureau of Entomology Bulletin 71:1-183.