FAMILY APODIDAE 227 



rump, and upper tail coverts light grayish brown, in some with very 

 narrow grayish white tips ; tail darker brown, with black shafts ; under 

 surface dull grayish brown (darker than the rump) ; throat and upper 

 foreneck slightly paler. 



Iris dark brown; bill black; tarsus sooty brown (Stone, Proc. 

 Acad. Nat. Sci. Philadelphia, vol. 70, 1918, p. 253). 



Measurements. — Males (10 from Trinidad and San Bias), wing 

 117.3-123.0 (119.6), tail 37.0-42.5 (40.7), oilmen from base 5.0-6.5 

 (5.8), tarsus 11.1-12.9 (11.7) mm. 



Females (10 from Trinidad, French Guiana, and Panama), wing 

 116.6-124.2 (120.2), tail 39.3-44.5 (41.3, average of 9), culmen from 

 base 5.7-7.3 (6.3), tarsus 11.0-12.2 (12.5) mm. 



Weight, 3 males 22\-26, 2 females 19f-23, 16 sex not known 

 21^-28 grams (data from Charles T. Collins). 



Status uncertain, possibly a migrant from South America. 



Two females were taken from a large flock at Gatun, Canal Zone, 

 July 9, 1911, by L. L. Jewel. At Mandinga, San Bias, I found several 

 flying over the Rio Cangandi on January 30, 1957, and shot a pair. 

 Others were seen high over the old airstrip on February 5. These are 

 the only definite reports for the Republic. Records attributed to birds 

 seen flying at Barro Colorado Island (Chapman, My Tropical Air 

 Castle, 1929, p. 402) are not certain, as no specimens were taken. 



In the air these swifts suggest Vaux's swift in outline, but when 

 seen clearly, are appreciably larger and heavier in body. In my view 

 of them at Mandinga as they passed overhead the wing appeared 

 broad toward the body. The tail, which is spread constantly as they 

 turn, was broad and fan-shaped. In general size they resemble the 

 northern chimney swift, with weights equivalent to the 22.2 to 25.6 

 grams of that species. 



The typical form of Chapman's swift is known mainly from speci- 

 mens and observations on Trinidad. It is recorded in South America 

 from the mouth of the Amazon (Para and Amapa) north through 

 the Guianas into Venezuela, where it has been taken in Amazonas 

 and Zulia. 



A slightly larger subspecies, Chaetura chapmani viridipennis de- 

 scribed from Mato Grosso, is recorded from Acre, Brazil, and Antio- 

 quia in northern Colombia. The wing in 3 specimens that I have 

 examined ranges from 127 to 128.8 mm. The supposed color differ- 

 ence of more greenish sheen on the wings is not constant. 



The species was named for Frank M. Chapman, who collected the 

 type and other specimens. 



