BIRDS OF NORTH AND MIDDLE AMERICA. 549 
ee. Larger, with relatively larger bill and shorter and less deeply forked tail, 
the lateral rectrices broader terminally; wing, 47-50.5, tail, 39-44, 
middle rectrices, 16-18.5, culmen, 14-15.5. (Cozumél Island, Yuca- 
tal \ie cio siscenasaeee Chlorostilbon forficatus, adult male (p. 552). 
dd. Tail much shorter than wing. (Chlorostilbon canivetti.) 
e. Tail longer and more deeply forked, the middle rectrices always distinctly 
tipped with gray; tail averaging 34.6, middle rectrices averaging 18.1. 
(Southeastern Mexico, including Yucatan, to British Honduras.) 
Chlorostilbon canivetii canivetii, adult male (p. 553). 
ee. Tail shorter and less deeply forked, the middle rectrices less distinctly 
(sometimes obsoletely) tipped with gray; tail averaging less than 32, 
middle rectrices averaging more than 18.5. 
jf. Maxilla more extensively brownish (or reddish) basally, never wholly 
blackish; middle rectrices usually with gray tip distinct; tail averaging 
longer and more deeply forked; wing averaging 45.8, tail 31.1, middle 
rectrices 18.6. (Guatemala, Honduras, and Salvadér.) 
Chlorostilbon canivetii osberti, adult male (p. 556). 
ff. Maxilla less extensively brownish (or reddish) basally, sometimes wholly 
blackish; middle rectrices usually with gray tip indistinct, sometimes 
obsolete; tail averaging shorter-and less deeply forked; wing averaging 
46, tail 27.9, middle rectrices 19.2. (Nicaragua and Costa Rica.) 
Chlorostilbon canivetii salvini, adult male (p. 557). 
ce. Maxilla wholly black; middle rectrices without trace of gray tip. 
d. Mandible pale (pink of reddish in life) basally; tail 32.5-38.5. (Porto Rico.) 
Chlorostilbon maugei, adult male (p. 550). 
dd. Mandible wholly black, like maxilla; tail 25.5-30. (Coast of Venezuela 
and islands of Trinid4d, Margarita, Aruba, Bonaire, and Curacao.) 
Chlorostilbon caribzeus, adult male (p. 559). 
bb. Forehead and crown dull metallic green, like back, etc. (Bill wholly black; 
wing averaging 45.6, tail 27.8, middle rectrices 19.4.) (Panam4 and south- 
western Costa Rica.).....-..-- Chlorostilbon assimilis, adult male (p. 558). 
aa. Under parts pale gray. (Adult females.) 
b. Outermost rectrix with a band of gray across middle portion. 
c. Whitish postocular streak minute; mandible wholly dusky; lateral rectrices 
narrower, with basal area of dusky not well-defined. 
Chlorostilbon maugzi, adult female (p. 550). 
cc. Whitish postocular streak conspicuous; mandible extensively pale basally; 
lateral rectrices broader, with basal dusky area well-defined. 
d. Tail averaging more than 31. 
e. Culmen 13-15.5 (14.2), tail 30-33.5 (31.7), the lateral rectrices narrower 
(about 4mm.)............ Chlorostilbon auriceps, adult female (p. 551). 
ee. Culmen 15.5-16.5 (15.8), tail 31-35 (32.8), the lateral rectrices broader 
(about 5-5.5 mm.)....... Chlorostilbon forficatus, adult female (p. 553). 
dd. Tail averaging less than 30. 
e. Tail averaging more than 29, the middle rectrices averaging less than 22. 
Chlorostilbon canivetii canivetii, adult female (p. 554). 
ee. Tail averaging less than 28, the middle rectrices averaging more than 22. 
f. Tail 27.5, the middle rectrices 23. 
d Chlorostilbon canivetii osberti, adult female (p. 556). 
Sf. Tail 25-28 (26.6), the middle rectrices 21-24 (22.7).a 
Chlorostilbon canivetii salvini, adult female (p. 557). 
bb. Outermost rectrix without any gray band across middle portion. 
ce. Culmen 13~-15.5 (14.3)......... Chlorostilbon assimilis, adult female (p. 558). 
ec. Culmen 16.5-17 (16.7).....-... Chlorostilbon caribzeus, adult female (p. 560). 
«The series of adult females of the different forms of C. canivetii is too small, espe- 
cially of C. c. osberti and C. c. salvini to admit of their satisfactory differentiation, 
