BIRDS OF NORTH AND MIDDLE AMERICA. 101 
Myrmelastes ceterus BANGS, Proc. New Engl. Zool. Club, ii, Sept. 20, 1900, 25 
(Loma del Leén, i. e., Lion Hill, Panamé; coll. E. A. and O. Bangs). 
[ Myrmelastes] ceterus SHARPE, Hand-list, iii, 1901, 32. 
GYMNOCICHLA NUDICEPS ERRATILIS Bangs. 
COSTA RICAN BARE-CROWNED ANTBIRD. 
Similar to G. n. nudiceps but averaging slightly larger, the adult 
female averaging more intense in coloration.? 
Adult male——Length (skins), 147-163.5 (153.5); wing, 75.5-83 
(78.9); tail, 59.5-64.5 (61.7); exposed culmen, 20-22 (20.9); tarsus, 
29.5-30.5 (30); middle toe, 19-20 (19.4). 
Adult female —Length (skins), 137.5-153 (148); wing, 72.5-77.5 
(75.1); tail, 56-62 (59.3); exposed culmen, 19-21 (19.9); tarsus, 
29-30 (29.4) ; middle toe, 18-19.5 (18.9).? . 
Southwestern Costa Rica (Boruca; Pozo del Rio Grande, Boruca; 
Térraba; Paso Real de Térraba; Buenos Aires; El General; Pigres), 
and northwestern Panama (Divala;* Mina de Chorcha; Bugaba; 
Chitra) ? i 
(2?) Gymnocichla nudiceps (not Myiothera nudiceps Cassin?) Satvin, Proc. Zool. Soc. 
Lond., 1870, 195, part (Mina de Chorcha and Bugaba, Verdgua, Panamé; 
crit.).—ScuaTer, Cat. Birds Brit. Mus., xv, 1890, 272, part (Mina de Chorcha, 
Bugaba, Chiriquf, and Chitra, Panam4).—Satvin and GopMaw, Biol. Centr.- 
Am., Aves, ii, 1892, 223, part (Chiriqui, Bugaba, Mina de Chorcha, and Chitra, 
Panam4). 
Gymnocichla nudiceps (not Myiothera nudiceps Cassin) CHERRIE, Expl. Zool. Merid. 
Costa Rica, 1893, 42 (Boruca, Térraba, and Buenos Aires, s. w. Costa Rica; 
crit.). 
Pri nudiceps erratilis Banas, Auk, xxiv, no. 3, July, 1907, 297 (Boruca, 
s. w. Costa Rica; coll. E. A. and O. Bangs).—Carriker, Ann. Carnegie 
Mus., vi, 1910, 620 (Costa Rica; crit.; habits). 
GYMNOCICHLA CHIROLEUCA Sclater and Salvin. 
BARE-FRONTED ANTBIRD. 
Similar to @. nudiceps but adult male with bend of wing white 
and white tips to wing-coverts broader, much less of concealed white 
on back, and bill paler (plumbeous in life, whitish—at least termi- 
nally—in dried skins); adult female with wing-coverts very much 
darker, contrasting much more strongly with their tawny or rufescent 
tips. 
Adult male—General color uniform black; bend of wing, broad 
tips to all the wing-coverts, and broad edging to outermost feather 
of alula and outermost primary, white; feathers of anterior portion 
@ The difference in coloration of temales is by no means constant, but the average 
difference is very obvious. 
6 Ten specimens. 
¢ Having only adult males from that locality, I am not able to determine whether 
specimens of this species from Divala belong to the present form or true G. nudiceps. 
No specimens from other localities in Chiriqui have been seen by me. 
