4l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



cinnamon-buff on crown and back ; crown streaked, and back spotted 

 heavily, with black ; rump, central upper tail coverts, and central tail 

 feathers blackish ; outer rectrices brownish gray, edged narrowly with 

 white; lesser and middle wing coverts brownish gray, with slightly 

 paler borders ; greater coverts, primaries, and secondaries dusky, 

 the coverts edged with white; line over eye white, lightly streaked 

 with dusky; loral space and center of forehead to base of bill 

 dusky brown; auricular region streaked with grayish brown; sides 

 of forehead and under surface white, with the breast and anterior 

 half of the sides streaked with dusky. 



Winter plumage, above grayish brown streaked, more or less nar- 

 rowly, with dusky ; superciliary, sides of forehead, and undersurface 

 white, with the upper breast streaked lightly with dusky. 



Iris brown ; bill, tarsus, and toes black. 



Measurements (from Ridgway, I.e., p. 211). — Males, wing 88-98.5 

 (93.9), tail 38-44.5 (41.2), exposed culmen 17-20 (18.6), tarsus 19- 

 21 (20.5) mm. 



Females, wing 92-101.5 (96.5), tail 40-44 (41.5), exposed culmen 

 18-22 (20.3), tarsus 20-22 (20.8) mm. 



Migrant from the north. Abundance not certain from the few 

 specimen records at present available ; probably of regular occurrence 

 with the great flocks of Ereimetes niauri. Some may remain during 

 the period of northern summer. 



The most definite character for separation of this species from the 

 western sandpiper is in the length of the bill, this being longer in the 

 latter. Since there is overlap in size between the female of the semi- 

 palmated sandpiper and the male of the western, this criterion may 

 be used with certainty only with birds of known sex, which implies 

 a specimen in the hand. In field observations occasionally a bird with 

 a very short bill — shorter than the head — may be accepted as a male 

 of the present species, but such records need to be considered with 

 caution. 



A specimen of the present species, collected by McLeannan, in the 

 British Museum that came from the Tweedale collection has a bill 

 length of 18.2 mm. There is no locality data other than Panama, but 

 it is probable that it is from the Caribbean slope. Bovallius secured 

 a female at Panama Viejo, February 26, 1882 (Rendahl, Ark. Zool. 

 vol. 12, no. 8, 1919, p. 11). Jewel collected a female (culmen 18.5 

 mm.) at Toro Point, Canal Zone, on September 4, 1911 (reported by 

 Stone, Proc. Acad. Nat. Sci., Philadelphia, vol. 70, 1918, p. 245). 

 Benson collected one at Aguadulce, Code, September 8, 1925 (speci- 



