Key to Scientific Names in Ornithology
(Tyrannidae; Ϯ Red-rumped Bush Tyrant C. erythropygius) Gr. κνημος knēmos mountain-slope; αρχος arkhos ruler, chief < αρχω arkhō to rule; "Cnemarchus gen. nov. (Tyrannidae) Somewhat like Myiotheretes Reichenbach, but tarsus relatively much shorter (much less than twice as long as the relatively shorter middle toe, with claw); claw of hallux not longer than its digit; wing only moderately lengthened, the longer primaries exceeding secondaries by much less than twice the length of tarsus and much less than one-third (instead of nearly one-half) the total length of wing; outermost (tenth) primary shorter than sixth (instead of equalling or exceeding ninth) and not attenuated at tip; tail more than two-thirds as long as wing, even (instead of emarginate), extensively rufous in color; bristly tips of latero-frontal feathers well-developed, arched; bill relatively much smaller, the exposed culmen not longer than outer toe, without claw; rump rufous but no rufous on remiges. Type, Tænioptera erythropygia Sclater = Cnemarchus erythropygius. (Kνημος, slope of a mountain; αρχος, ruler, chief.)" (Ridgway 1905). The Red-rumped Bush Tyrant was described from the high Andes of Ecuador.