1885. J PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 27 



haps not from that island, agree substantially with the type. Two of 

 them, however, have much less gray on the forehead, and the yellow 

 superciliary stripe commences immediately above the eye. Another, 

 undoubtedly from Dominica, and without question an immature bird in 

 transition plumage, has the forehead tinged with yellow. 



Having had occasion, in connection with the determination of the above- 

 described forms, and also with the comparison of a series of G. cahoti from 

 Cozumel, to carefully examiiie the entire collection of these birds in the 

 ifationa Museum, the desirability of a new synoptical " key " to the species, 

 became apparent. The subject was carefully and satisfactorily brought 

 up to date in 1874 by Professor Baird (see Hist. ¥. Am. B., I, pp. 426-428) 

 but material for study, and consequently our knowledge of the subject, 

 has been increased somewhat since the publication of Professor Baird's 

 synopsis. The following key is based entirely on the National Museum 

 collection, embracing some two hundred skins. It may be premised 

 that division of the genus into groups or sections is somewhat difficult, 

 from the fact that almost any character which may be selected to define 

 these is more or less variable. Thus, in some forms it is difficult, if possi- 

 ble, to determine satisfactorily whether the head is concolorwith the back 

 or darker ; while as to the wing-spot, one species of the group said to 

 have none has occasionally a very obvious though small, " speculum"; 

 while, on the other hand, a species of the other group has the speculum 

 sometimes so reduced in size as to be practically obsolete. 



KEY TO THE SPECIES OF THE GENUS CERTHIOLA. 



A. — Plumage parti-colored (blackish, yellow, white, &c.). 



a. A distinct white spot or "speculum" at base of primaries (rarely obsolete in 

 C. mexicana coluniMana). 

 $. Throat grayish white. 

 jf_ '-i-'- 1. C. bahamensis. Yellow confined to breast; black loral streak very nar- 

 row ; cheeks white almost to the eye ; both webs of outer rectrices broadly 

 tipped with white. Mab. Bahamas ; coast of southern Florida. 

 -J. 2. C. caboti. Yellow extended over abdomen and flanks ; black loral streak 

 broader than the white above it, and continued broadly beneath the eye ; 

 white tip of outer tail-feather smaller, and mainly confined to inner web. 

 Back darker. Hab. Cozumel I., Yucatan. 

 3. C. tricolor. Similar to C. caboti in extent of the yellow beneath, but agree- 

 ing with C. bahamensis in narrow loral and suborbital streak, broad white 

 tips to both webs of outer rectrices, and larger wing spot ; back darker 

 even than in C. caboti. Hab. Island of Old Providence, Caribbean Sea. 

 $§. Throat light ash-gray. 



J- 4. C. mexicana. Back brownish slate ; rump olive-green or olive-yellow ; 

 inner web of outer tail feathers with small terminal spot of white ; wing- 

 spot small, sometimes nearly obsolete ; wing not more than 2.30 inches. 

 - a. Mexicana. Rump olive-green. Sab. Mexico and Central America 



to Chiriqui. 

 .-^ /?. Columbiana. Rump olive-yellow. Hab. Panama to Peru. 



