THE GENUS CHOEDEILES SWAINSON" OBEEHOLSER. 99 



Chars, suhsp. — Similar to Chordeiles acutipennis acutipeTtnis, but 

 upper surface paler and averaging rather less grayish, more brownish 

 in general effect; lower parts paler, the dark bars of a lighter brown, 

 somewhat narrower, and noticeably farther apart with consequently 

 broader white interspaces; light bars on tail broader and on under 

 side averaging paler ; chest and jugulum lighter. 



Measurements. — Total length (in flesh), 195-208 mm.; extent of 

 wing, 457-488. 



Male:^ Wing, 155-162 (average, 158.5) mm.; tail, 95-96.5 (95.8) ; 

 exposed culmen, 4.2-4.3 (4.3) ; tarsus, 13.7-14.3 (14) ; middle toe, 

 12.3-12.8 (12.6). 



Type-locality. — Northern Chile. 



Geographical distribution. — Permanently resident in the Lower 

 Tropical Zone of the Pacific slope of central South America, north to 

 Callao and Lima, central western Peru, and south, probably, to 

 northern Chile. 



Remarks. — This race is almost unique in its paleness below, which 

 is due to the width of the light interspaces and to their whiteness. 

 An unfortunately small series has been available, but the subspecies 

 is evidently a good one, though it occupies a very restricted geo- 

 graphical area. A single juvenal male skin of ancient make, said to be 

 from Bolivia, was probably obtained somewhere within the present 

 confines of Chile, though the territory may have owed allegiance to 

 Bolivia when this specimen was procured. 



The first autumn plumage of Chordeiles acutipennis exilis is simi- 

 lar to that of Chordeiles acutipennis acutipennis in the gray phase, 

 but is much paler, more silvery above; lighter, more grayish, and 

 more finely vermiculated on the jugulum. In color of both upper and 

 lower parts it is almost exactly like first autumn Chordeiles vir- 

 ginianus sennetti, though slightly more buffy on the posterior portion 

 of the ventral surface, and, of course, smaller, with the light spot on 

 the wing-quills nearer their ends. 



This race is commonly Imown as Chordeiles axmtipennis pruinosus^ 

 but an earlier name is found in Caprimulgus exilis of Lesson.^ This 

 without any reasonable doubt is applicable to the pale bird from 

 Peru; and the main reason for its rejection hitherto has been its type 

 locality of " Chile." The northern part of this country is still imper- 

 fectly known ornithologically, and the occurrence of this bird there 

 is at least probable, even within what was formerly the northern 

 boundary of that country. At any rate, the description is a good 



^ Two specimens, from Peru. 



2 Caprimulgus pruinosiis TschudI, [Wiegmann's] Archiv fOr Naturg., 1844, p. 268 (Peru) 

 (Lichtenstein JIS.). 



3 Rev. Zool., 1839, p. 44. 



