522 Annals of the Carnegie Museum. 



they belong. To those authors who may find their names reduced to 

 synonymy these considerations are respectfully commended. 



Geographic variation. — This mainly affects the size, general intensity 

 and shade of coloration of the upper and under parts and wing- 

 coverts, the extent of the plumbeous or cinereous area on the crown 

 and nape, and the color of the bill. As shown by the table of measure- 

 ments on page 592, the average sexual difference in size is very little- 

 The three forms from continental North America, C. p. passerina* 

 C. p. pallescens, and C. p. neglecta, are the largest, while the form from 

 the interior of Colombia, C. p. parvula, is remarkably small, the 

 remaining forms being intermediate in this respect. The exact shade 

 of color varies greatly, as may be seen by comparing two such forms 

 as C. p. socorroensis and C. p. exigua. Two forms, C. p. albivitta and 

 C. p. antillarum, have a peculiar lavender gray cast to the plumage, 

 occasionally obvious also in C. p. quitensis and C. p. aflavida. There 

 is a tendency in some of the South American forms towards the 

 expansion of the brownish area of the crown and nape, the grayish color 

 becoming obsolete. 



It is the matter of the color of the base of the bill in life, however, 

 that has perhaps given the most trouble, owing of course to want of 

 exact information in many cases. No doubt the color varies some- 

 what with age, as in other species, but after allowing for this there 

 would seem to be four types of coloration occurring, each fairly 

 constant for adult birds of the respective species involved. In 

 C. p. passerina, C. p. albivitta, and C. p. jamaicensis, for example, 

 the basal half or two-thirds of the bill is yellow or orange yellow in 

 life, this color fading to dull yellowish in the dry skin, but leaving the 

 bill conspicuously bicolor in appearance. In C. p. pallescens, C. p. 

 neglecta, C. p. quitensis, and C. p. trochila the base of the bill is more 

 or less crimson, which becomes dusky brownish upon drying, giving 

 a much more uniform effect. C. p. antillarum is said to have the 

 base of the bill clear olive or olive-brown in life, while in C. p. baha- 

 mensis it is almost wholly black. We are greatly indebted to Dr. 

 Percy R. Lowe for our present knowledge along this line, especially 

 as regards the various Antillean forms, which otherwise would be 

 much more difficult to discriminate. FAs Dr. Lowe points out, even 

 if no other distinctive characters were available, there can be no 

 justification for "lumping" such forms under one name, as Count 

 Salvadori has done. 



