MUSEUM OF COMPARATIVE ZOOLOGY. 191 



black spotted with white, as in some of the woodpeckers (Picus villosus 

 and P. pubescens, for example), the white markings vary in size most 

 notably, and sometimes in number. The wliite markings so common 

 on the wings and tails of birds, as the bars formed by the white tips of 

 the greater wing coverts, the wliite patch occasionally present at the 

 base of the primary quills, or the white band crossing them, and the 

 white patch near the end of the outer tail feathers, are also extremely 

 liable to variation in respect to their extent and the number of feathers 

 to which, in the same species, these markings extend. Variation in the 

 tail markings is particularly common, as may be seen by comparing 

 numerous specimens of almost any species of Dendrceca, Junco, Pipilo, 

 of Mimus polyglottus, Chordeiles popetue, etc. In the latter species the 

 white patch on the wing does not ordinarily encroach upon the outer 

 vane of the first primary, and rarely upon its shaft, but in several spe- 

 cimens before me it covers not only the shaft of the first primary, but 

 extends completely across its outer vane ! The black subterminal bar 

 on the upper surface of the tail of the ruflfed grouse (Bonasa umbellus) 

 ordinarily crosses all but the middle pair of feathers, on which there is 

 usually no trace of this bar; in many specimens, however, it is barely 

 traceable on them, and in others it is as distinct and perfect on the 

 middle pair as on the others.* 



The Parula americana presents also remarkable examples of indi- 

 vidual color variation. The colors of the males are usually much 

 brighter than those of the females, but cases are frequent where the sex 

 cannot" be determined by the color of the plumage. Adult males also 

 vary greatly in the style of coloration. They are generally bright 

 yellow anteriorly below, with a broad band of dusky reddish-brown 

 across the breast, varying in tint from nearly pure chestnut to dusky 

 reddish-brown, and even black, and also greatly in extent. In some, 

 however, this band is partially obsolete, in which case the whole plu- 

 mage is generally paler than in average specimens. More rarely large, 

 brightly colored males are taken, even in New England, with the whole 

 breast bright yellow, the brownish pectoral band being entirely absent. 

 This condition, however, seems to be more frequent in specimens of 

 Parula collected in Mexico, and Central and Northern South America, 

 which on this account have been regarded as distinct from the Parula 

 of the North ; yet all the conditions of color seen in specimens from 



* See remarks on color variations in other species in Part IV. 



