BIRDS OF NORTH AND MIDDLE AMERICA. 315 
Large Tringine (wing 175-220 mm.) with the very stout bill 
nearly as long as tarsus; a distinct web between basal portion of 
inner and middle (as well as between outer and middle) toes, and with 
basal portion of primaries extensively white. 
Bill nearly as long as tarsus, stout, but compressed, its depth at 
base equal to about one-sixth the length of exposed culmen; nasal 
groove broad, extending about half way to tip of maxilla; nostril 
considerably anterior to loral antia, narrowly elliptical, longitudinal. 
Wing ample, pointed, the longest primary (outermost) exceeding 
distal secondaries by less than half the length of wing. Tail 
more than one-third as long as wing, truncate or very slightly 
rounded; rectrices12. Tarsus decidedly more than one and a half times 
as long as middle toe without claw, continuously scutellate both 
anteriorly and posteriorly; bare portion of tibia about half as long 
as tarsus, scutellate behind and for upper portion in front; oviter toe 
slightly but distinctly shorter than middle toe, slightly longer than 
-inner toe; basal phalanges of outer and middle toes united by a web, 
the inner and middle toes united at base by a slightly smaller web. 
Coloration.—Under parts and upper tail-coverts mostly white, the 
primaries extensively white basally, blackish or dusky distally; rest 
of plumage brownish gray, in summer streaked and barred or spot- 
ted, more or less with blackish. 
Range——North America (South America in migration.) (Mono- 
typic.) 
KEY TO THE SUBSPECIES OF CATOPTROPHORUS SEMIPALMATUS. 
a. Smaller, with relatively shorter and thicker bill (wing, 175-195.5; tail, 66.5-74; 
‘exposed culmen, 52.5-59; tarsus, 51.5-58; middle toe, 31.5-36); summer adults 
with upper parts darker, more olive-grayish, more heavily spotted or barred 
with dusky, and with anterior and lateral under parts more heavily marked 
with dusky. (Eastern United States; Bahamas; etc.). 
Catoptrophorus semipalmatus semipalmatus (p. 315). 
aa. Larger, with relatively longer and more slender bill (wing, 193-220; tail, 73-88; 
exposed culmen, 56-65; tarsus, 57-70; middle toe, 32.5-39); summer adults 
with upper parts paler, more ashy gray, less heavily marked with dusky, the 
anterior and lateral under parts also less heavily marked. (Western United 
States, British Columbia, Alberta, etc., east to Mississippi Valley; occasional 
during migration along Atlantic and Gulf coasts.) 
Catoptrophorus semipalmatus inornatus (p. 319). 
CATOPTROPHORUS SEMIPALMATUS SEMIPALMATUS (Gmelin), 
WILLET. 
Adults in summer (sexes alike).—General color of upper parts 
brownish gray, the pileum and hindneck streaked with dusky, the 
back and scapulars irregularly spotted and barred with dusky or 
blackish; wing-coverts nearly plain brownish gray, becoming paler 
on greater coverts; secondaries largely white; primaries white for 
