- Edoliisoma elusum McGregor, Bureau Govt. Laboratories, Manila (1905), 34, 19; McGregor and Worcester, Hand-List (1906), 77.
Luzon (Celestino); Mindoro (McGregor).
Male.—Similar to the male of E. mindanense, but rump and upper tail-coverts bluish slate-gray like the back and not lighter pearl-gray.
Description of type.—General color bluish slate; chin, throat, fore breast, forehead, and sides of head, including lores and a wide line over eye, jet-black; alula, primary-coverts, and primaries black; inner primaries and inner feathers of alula narrowly edged with gray; secondaries black with wide edges of blue-gray, which cover nearly the entire outer web; secondary-coverts gray; inner webs of quills partly dark blue-gray, this begins as a small basal area on the short first primary, becomes greater on each succeeding quill, and reaches nearly to the tips of inner quills; a narrow edging of white on inner webs of first four quills; tail black; from below outermost pair of rectrices tipped with blue-gray (20 mm. in length); on second pair the gray tip much less, and only a trace on some of the other rectrices; central pair blue-gray above, with a subterminal black area. Length, 236; culmen from base, 22; bill from nostril, 16; wing, 127; tail, 106; tarsus, 23.
Female.—Similar to the female of E. mindanense, but rump and upper tail-coverts slate-gray like the back; abdomen and crissum gray like the breast, not lighter as in E. mindanense. Length of female type, 236; culmen from base, 22; bill from nostril, 15; wing, 126; tail, 106; tarsus, 23.
The elusive cuckoo shrike seems to be closely related to E. everetti, but no direct comparison can be made as the latter species is not represented in the Bureau of Science collection.
Genus PERICROCOTUS Boie, 1826.
Bill short and slightly flattened; wing and tail nearly equal in length, or wing shorter than tail; rectrices very narrow and strongly graduated, the outermost pair being less than one-half the middle pair. Length usually less than 200 mm. Excepting the gray and white P. cinereus which is migratory, the Philippine species are glossy black and some shade of bright yellow, red, or orange.