BIRDS OF NORTH AND MIDDLE AMERICA. 245 



Bill variable as to relative length, sometimes equal to or slightly 

 longer than head (exposed culmen shorter than middle toe without 

 claw and longer than toe with claw), sometimes much shorter, but 

 always slender and appreciably decurved terminally, and with 

 breadth at frontal antiae about equal to its height at same point; 

 culmen nearly straight basally, gradually becoming more decurved 

 toward tip ; gonys nearly straight (usually slightly concave in middle 

 portion, its hase decidedly anterior to nostril; maxillary tomium 

 gently concave, distinctly notched subterminally. Nostril hori- 

 zontal, narrow (narrowly oval, elliptical, or linear), overhung "by 

 narrow membrane, posteriorly in contact with feathering of frontal 

 antia?. Rictal bristles obvious, but few. and weak. Wing rather 

 long and pointed, the longest primaries exceeding longest secondaries 

 by length of middle toe (without claw) or more, the eighth and 

 seventh, or eighth, seventh, and sixth, primaries longest, the ninth 

 very much longer than secondaries, the tenth (outermost) not more 

 (usually less) than half as long as ninth. Tail not longer than wing 

 (usuall}" decidedly shorter), strongly rounded (the graduation about 

 equal to length of exposed culmen or to length of middle toe without 

 claw). Tarsus long and slender (slightly less to more than one-third 

 as long as wing, always decidedly longer than exposed culmen, some- 

 times twice as long), the acrotarsium distinctly scutellate; middle 

 toe (without claw) decidedly less than two-thirds as long as tarsus; 

 lateral toes unequal, the inner (without claw) reaching to subterminal 

 joint of middle toe, the outer slightly beyond; hallux shorter than 

 inner toe but much stouter; claws normal in size and curvature; 

 basal phalanx of middle toe adherent to that of outer toe for about 

 half its length, to that of inner toe for basal portion only. 



Coloration. — Upper parts variegated with brownish gra}^ (or 

 grayish brown), dusky, and whitish; beneath dull whitish, streaked 

 on flanks with dusky, the chest or sides of breast sometimes spotted 

 with dusky. Young with under parts always spotted on chest, etc. 



Nidijication. — Nest and eggs essentially like those of the genus 

 Mimus. $ 



Range. — Galapagos Archipelago. (Eleven species, or forms.) 



KEY TO THE SPECIES OF NESOMIMUS. 



a. Upper parts without streaks, but (in unworn plumage) the pileum and back more or 

 less transversely marked with white; auricular region white; a large patch of 

 dusky on each side of chest; iris dark brown. (Gardner Island, near Charles, 

 and Champion Island, Galapagos Archipelago.). . .Nesomimus trifasciatus (p. 247; 

 aa. Upper parts streaked, and without transverse markings of white; auricular region 

 dusky; no dusky patch on sides of chest; iris yellow. 

 b. Breast crossed by an interrupted band of dusky spots. 

 c. Bill much larger (exposed culmen 31.5-33), more curved; spotting on breast 

 more distinct. (Hood Island, Galapagos Archipelago.) 



Nesomimus macdonaldi (p. 248) 



