240 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



parts fine slate-blue, tbe dorsal and scapular plumes paler, more pearl- 

 grsky — the lightness of the tint proportionate to the length of the plume; 

 remiges black, the inner secondaries growing gradually more slaty, so 

 that the innermost are scarcely darker than the tertials. Tail deep 

 slate-blue, a shade darker than the tertials. Entire border of the wing, 

 from the armpit to the metacarpophalangeal joint, rich purplish-rufous, 

 scarcely mixed anywhere with white, and much the widest at the bend. 



Wing, 17.90-20.00; tail, 7.30-8.00; culmen, 4.30-6.25; depth of bill, 

 through middle of nostril, 0.85-1.10; naked portion of tibia, 3.50-5.70; 

 tarsus, G.00-8.25 ; middle toe, 3.50-4.70. [Extremes of 17 adult speci- 

 mens.] Bill olive above, the culmen blackish; lower mandible wax- 

 yellow, brighter terminally (sometimes wholly yellow) ; iris bright yel- 

 low; bare loral space cobalt-blue in spring, olive-greenish or yellowish 

 after breeding season. Legs and feet duslcy-hlack throughout. 



Young. — Above slate-gray (less bluish than in the adult), destitute of 

 any penicillate plumes; anterior lesser wing-coverts bordered terminally 

 with light rufous; border of the wing (broadly) white, more or less 

 tinged with rufous, especially at and near the bend, where this color pre- 

 vails. Entire pileum, including all the occipital feathers, blackish-slate, 

 with a narrow median crest of more elongated darker-colored feathers, 

 with pale fulvous shaft-streaks. Cheeks dark grayish; malar region, 

 chin, and throat only, pure white. Neck dull gray, sometimes tinged 

 with rufous, some of the feathers with indistinctly lighter shaft-streaks; 

 foreneck with a narrow longitudinal series of black, rufous, and whitish 

 dashes, much as in the adult. Breast and abdomen broadly striped 

 with dark cinereous and white, in nearly equal amount (sometimes suf- 

 fused with rufous). Tibiae very pale rufous, sometimes almost white; 

 crissum white. Upper mandible black, paler, or horn-color, along the 

 tomium; lower, pale pea-green, deepening into clear horn yellow on 

 terminal half; ej^elids and horizontal space on lore light apple-green ; 

 iris gamboge-yellow; tibiae and soles of toes, apple-green; rest of legs 

 and feet black.* 



Geographical and individual variations. — So far as is indicated by the 

 ratherscantmaterial before me (17 adult specimens), there is little, if any, 

 variation in i)roportions or colors which can be considered strictly geo- 

 graphical. Especially is this so with regard to dimensions and relative 

 measurements of different parts in an individual, — a fact which is clearly 

 shown by the annexed table of carefully-made measurements. The 

 typical style, indeed, prevails with such uniformity that of the seventeen 

 specimens now before me, only four differ in any noteworthy respect 

 from the average style. These "aberrant" examples are the follow- 

 ing:— 



No. 68300, from Florida, is decidedly the largest in the whole series, 

 its general size almost equalling that of A. occidentalis. The bill also 

 approaches quite nearly to that of the latter species, both in size and 



* Notes takeu from fresh specimeu [No. J050, Coll. R. R., 9 juv.. Mount Carmel| 

 Illinois, Sept. 26, 1870. Length, 42.00; expanse, 68.50]. 



