228 FORMICARIIDZ. 
numbers ; but specimens were not easily secured, as the bird runs on the ground very 
swiftly, and hides amongst the leaves. It utters loud, rather musical notes, resembling 
those of the Golden-crowned Thrush of the United States. 
4. Myrmelastes occidentalis, 
Myrmeciza immaculata, Pr. U. 8. Nat. Mus. v. p.398*; Zeledon, An. Mus. Nac. Costa Rica, 1887, 
p- 115 (partim) °*. 
Myrmeciza immaculata occidentalis, Cherrie, Auk, viii. p. 191°. 
M. sclateri persimilis, et mares forsan haud distinguendi; femina pallidior, et subtus gutture inferiore et pectore 
leete castaneis haud castaneo-brunneis dignoscenda. 
Hab. Costa Rica, La Palma (Nutting!), Las Trojas, Pozo Azul de Pirris (Zeledon *), 
Bebedero (F. C. Underwood *). 
This bird is very closely allied to UM. intermedius, but as it is apparently separated 
by the great mountain-range of Costa Rica from its relative a distinctive name for it is 
perhaps desirable. Mr. Ridgway has kindly lent us a typical male and three females 
of this form, and comparing them with a series of twelve examples of IZ. intermedius, we 
find no tangible difference in the males, but the females of I. occidentalis ave decidedly 
of a brighter chestnut on the breast and lower part of the throat. Mr. Cherrie speaks 
of a decided difference of size; but his measurements only show an average difference 
in the length of the wing of ‘02 inch, which does not strike us as of any importance 
whatever. 
The range of this form is, according to Mr. Cherrie, restricted to the lowlands of 
Costa Rica bordering the Pacific Ocean. How far south-eastwards it extends we are 
unable to say, as we have only male specimens from Chiriqui, and these do not show 
to which form they belong. 
Several specimens in the National Museum of Costa Rica are noted as having the 
bare orbital skin cobalt-blue, and the iris as chestnut °. 
f'. Plume supranasales normales. 
MYRMECIZA. 
Myrmeciza, Gray, List Gen. Birds, p. 34 (1841) ; Scl. Cat. Birds Brit. Mus. xv. p. 277. 
Myrmeciza as at present constituted contains rather a heterogeneous group of species, 
but we do not propose to recast the genus, beyond removing from it M. ersul and 
M. immaculata, which come much better into the genus Myrmelastes. ‘This leaves ten 
or eleven species in Myrmeciza, whereof three occur within our limits. Of these, the 
