1. Marginal setation of forelegs thickly positioned; cerci relatively uniform in coloration (without distinctive light and dark bands), only sometimes graying distally; mature body 4-6 mm; hindwingpads absent or sometime represented by scalelike or straplike vestiges. . . . . . . . . . . . . . . 2Marginal setation of forelegs less thickly positioned; cerci usually with many light and dark bands (variously distinctive, sometimes not apparent); smaller species with mature body less than 4 mm; hindwingpads not developed, but vestigial and straplike. . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Forelegs with tibia and tarsus together relatively long (distinctly longer than femur); gills not pigmented; abdominal tegum 9 and 10 (and sometimes posterior of 8) lighter compared to; terga 7 and 8 (or 7 and anterior of 8); fresh specimens very seldom with redish coloration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acentrella tubida
Forelegs with tibia and tarsus together relatively short (about as long as femur); gills pigmented basomedially; abdominal terga 8-10 lighter compared to tergum 7; fresh specimens sometimes with reddish coloration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acentrella nadineae
3. Body and cerci with highly contrasting light and dark areas; gills often with some pigmentation (small blotch in distal half of gill); length of vestigial median caudal filament; usually less than basal width of cerci. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acentrella parvula
Gills clear. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acentrell rallatoma
Key to Ohio Acentrella Nymph Species