434 BIKES OF ILLINOIS. 



nine feet from the ground, its location being a shallow cavity, 

 caused by the breaking off of the main limb, the upper part of 

 which projected over sufficiently to form a protection from the sun 

 and rain. 



SUBGENUS JEsalon KAUP. 



jfEsalon KAUP, Sk. Ent, Eur. Thierw. 1829, 40. Type Falco cesalon GMEL. 



The species of this subgenus may be distinguished by the follow- 

 ing characters: 



COMMON CHAKACTERS. Adult males plumbeous blue above, the feathers with dusky 

 shafts; tail more or less banded with black, and tipped with whitish. Beneath whitish, 

 buffy, or light rusty, striped with brownish. Adult females. Above brownish, with 

 darker shaft-streaks. Tail usually with five to eight, more or less distinct, lighter bands 

 (all but the terminal one sometimes obsolete in F. suckleyi). Beneath whitish, buffy, or 

 ochraceous, striped with dusky or brownish. Young (both sexes}. Similar to the adult 

 female, but colors softer, more blended. 



A. Tail of adult male with six imperfect blackish bands, besides the subterminal broad 

 black zone. Adult female and young with about eight light bands, including the ter- 

 minal one. 



(F. regulus, of Europe and Northern Asia.) 



B. Tail of adult male with only three or four blackish bands, besides the broader sub- 

 terminal one. Adult female and young never with more than six light bands, includ- 

 ing the terminal one. 



1. F. richardsoni. Adult male. Above pearl-blue or pale ashy blue, the crown 

 more or less tinged with ochraceous. Tail crossed by five dark and six light 

 bands, the latter more or less mixed or clouded with white; outer webs of pri- 

 maries distinctly spotted with light bluish gray, the inner web of the longest 

 with eight white spots. "Mustache" obsolete, or but very slightly indicated. 

 Lower parts buff, or buffy white, the tibi;B and a nuchal collar more ochraceous. 

 Breast, etc., rather broadly striped with brownish. Wing, 7.70-8. 60; tail, 5.00-6.00; 

 culmen, .50-.60; tarsus. 1.42-1.55; middle toe, 1.20-1.30. Adult female. Above 

 earthy brown, more or less distinctly marked with transverse spots of a lighter 

 shade. Tail with six very distinct and perfectly continuous whitish bands; 

 secondaries distinctly banded with ochraceous, and outer webs of primaries 

 distinctly spotted with a lighter tint of the same. Beneath white or buffy, the 

 breast, etc., broadly striped with light brown. Wing, 8.50-9.00; tail, 6.00-6.30; cul- 

 men, .55-.5S; tarsus, 1.55-1.65; middle toe, 1.35-1.40; Young. Similar to the adult 

 female, but more decidedly buffy below, the upper parts more or less tinged 

 with rusty. 



2. F. columbarius. Adult male. Above much darker plumbeous. Tail crossed by 

 not more than four dark or five light bands (including terminal one). Adult 

 jemale and young. Very variable in color, but tail never with more than four 

 dark or five light bands, including the whitish tip. 



OC. columbarius. Adult female and young with distinct light spots on inner 

 webs of primaries, and the light bands on the tail more or less distinct. 

 Male: Wing, 7.20-7.90; tail, 4.90-5.50; culmen, .48-.50; tarsus, 1.30-1.40; middle 

 toe,].15. Female: Wing, 8. 00-8.55; tail, 5.50-6.00; culmen, .55-.60; tarsus,1.55- 

 1.60; middle toe, 1.35-1.40. 



P. suckleyi. Adult female, and young, without distinct spots on inner webs 

 of primaries, or light bands on tail (except the whitish tip), these 

 markings being sometimes wholly obsolete. General color much darker, 

 the lower parts even with dusky predominating. Male: Wing, 7.35-7.70 ; 

 tail, 5 25-5. 60; culmen, .48-.50; tarsus, 1.30-1. 45; middle toe, 1.20. Female: Wing, 

 8.25-8.50; tail, 5.70-5.80; culmen. .55-.60; tarsus, 1.50-1.60; middle toe, 1.35-1.40. 

 (Adult male unknown!) 



