a1. First primary abruptly attenuated.b1. Tail rather long; pectoral feathers not bifurcated. Leucotreron (p. 37)b2. Tail moderate; pectoral feathers bifurcated. Lamprotreron (p. 40) a2. First primary not so abruptly attenuated; slightly narrowed at tip. Spilotreron (p. 41)
a1. First primary abruptly attenuated.b1. Tail rather long; pectoral feathers not bifurcated. Leucotreron (p. 37)b2. Tail moderate; pectoral feathers bifurcated. Lamprotreron (p. 40)
a2. First primary not so abruptly attenuated; slightly narrowed at tip. Spilotreron (p. 41)
