1. Mesofemora each with ventral seta 3 arising in line with dorsal seta 1 or distal to it by no more than approximate distance between ventral setae 4 and 5; head setae no. 17 subequal to or greater in thickness than setae 15 and more than 1/2 length of setae 15, generally dark brown; head black with whitish or yellowish markings formiing distinctive patterns of broad dark or light longitudinal bands, these bands continuing onto thoracic nota. . . . . . . . . Psilotreta indecisa
Mesofemora each with ventral seta 3 arising distal to dorsal seta 1 by more than distance between ventral seta 4 and 5; head seta no. 17 much thinner than setae 15 and no longer than 1/2 length of setae 15, colorless to light brown; head uniformly reddish brown or with pale ares laterally; thoracic nota niformly reddish brown to pale yellowish, or with indistinct darker markings marginally. Rare, reported in just 2 counties, Venton and Guernsey. . . . . . . . . . . . . . . . . . . . . . . . . . . Psilotreta rufa
Key to Species of Psilotreta Nymphs