BIRDS OF NORTH AND MIDDLE AMERICA. 613 
Downy young.—Dull buffy grayish white, the under parts (except 
throat) immaculate; head marked with irregular spots of black, 
irregularly distributed; back, wings, and rump clouded with dusky 
grayish; bill black, tipped with yellowish; legs and feet brownish (in 
dried skins). ~ 
Adult male.—Wing, 401-419 (410); tail, 162.5-168 (165.2); ex- 
posed culmen, 52.5-56 (54.2); tarsus, 60-62 (61); middle toe, 
57.5-59.5 (58.5).@ 
Adult female—Wing, 401-417 (407.5); tail, 159-166 (161.4); ex- 
posed culmen, 45.5-51.5 (48.4); tarsus, 54-59 (56); middle toe, 
49-53 (51.2).° 
a Two specimens. b Five specimens. 
Ex- 7m 
Locality. Wing. | Tail. | posed |Tarsus. ee 
‘ culmen " 
MALES. 
One adult male from England.........--..-.-----.-2--022.005- 401 162.5 56 60 57.5 
One adult male from France. ..........2...2--eee cece eee e eee ee 419 168 52.5 62 59. 5 
Six adult males from North America (L. a. smithsonianus)..... 452 | 177.1 60 66.1 59.7 
FEMALES. 
Three adult females from England (2) and Scotland (1)...... -| 404.7] 163 47.7 56 51 
One adult female from Germany... 2.0.2. 4.0. 00.000ceeseeeeyecees 408 159 51.5 56 52 
One adult female from Cumberland Gulf..................----- 417 159 BSS i ccannsce eaensined 
Four adult females from North America (L. @. smithsonianus).| 426 173.5 55.2 60. 5 55.5 
In view of the paucity of material examined, I follow the decision of the A. O. U. 
Committee in uniting the North American and European birds of thisspecies. Never- 
theless, the differences in size and coloration in the series examined are so marked that 
{ cannot help believing that careful and unbiased examination of adequate material 
will show that they are separable as subspecies. The series examined by me plainly 
shows the following difference between the North American and European birds (see 
“Key” on p. 582): — ° 
k. Smaller (wing 401-419, averaging 410 in male, 405.5 in female; culmen 45.5-56, 
averaging 54.2 in male, 48.6 in female; tarsus 54-62, averaging 61 in male, 56 in 
female; outermost primary with terminal white area usually without interruption 
by a subterminal black bar, the latter if present very small and rarely continu- 
ous. (Northern Europe, southward in winter to Mediterranean, Black, and Caspian. 
seas; occasional in northeastern North America.)..... Larus argentatus argentatus. 
kk. Larger (wing 417-465, averaging 452 in male, 424.2 in female; culmen 48-63. 
averaging 60 in male, 53.8 in female; tarsus 58-68, averaging 66.1 in male, 60.5 
in female; outermost primary with white on terminal portion usually divided 
into two separate areas by a subterminal spot or bar of black, this rarely less 
than 12.5 mm. wide, often extending to extreme tip, then reducing the white to 
a subterminal spot. (Northern North America, southward in winter to Bahamas, 
Cuba, Yucatan, western Mexico, etc.)....-..--- Larus argentatus smithsonianus. 
The European birds are probably divisible into two forms. 
