Above light ash-color. Upper tail-coverts and forehead much lighter than the back, the former sometimes almost white. Sides and breast generally nearly pure white.
Black of loral space with conspicuous hoary margin above it. Inner web of secondaries much as in C. ludovicianus. Axillars whitish. Tail-feathers with concealed white patch at bases of all the feathers. Bill from nostril about .50. No waved lines beneath. White patch on wing reaching nearly opposite to end of first primary. Tarsus longer than the gape. Length, 8.50; wing, 4.05; tail, 4.25; bill above, .83; tarsus, 1.12 … excubitoroides.
PLATE XIX.
1. Collurio borealis, Vieill.♂ H. B. T., 19549.
2. Collurio borealis, Vieill. juv., 17192.