1904.1 NATURAL SCIENCES OF PHILADELPHIA. 447 



A MONOGRAPH OF THE GENUS DENDROCINCLA Gray, 

 BY HARRY C. OBERHOLSER. 



The purpose of the investigation -whose results are set forth in the 

 following pages is to clear up to such degree as may be possible the 

 measurable uncertainty of identification attending the birds of the 

 genus Dendrocinda. This Dendrocolaptine group is composed en- 

 tirely of plainly attired species which present often but slight differ- 

 entiating characters; and many of the original descriptions are both 

 so short and so unsatisfactory that the determination of their positive 

 identity is a matter sometimes of considerable difficulty. Individual 

 color variation is very marked in a few of the forms, occasionally 

 amounting to a greater degree of difference than that which distin- 

 guishes some entirely distinct species; and the sexes, though alike in 

 color, frequently differ widely in size. The color of the bill, which some 

 writers have relied on to furnish specific distinctions, seems to change 

 with age, being darkest in immature birds. 



The name Dendromancs^ under which Dr. Sclater proposed to sepa- 

 rate Dendrocinda anahatina and a few of the other small species, at 

 first generically,^ then subgenerically,- seems to have no standing other 

 than as a simple synonym of Dendrocinda, since the alleged characters 

 do not prove to be significant; furthermore, there are no other struc- 

 tural differences among the species of the genus, aside from some com- 

 paratively slight variations in length of tail, and none of these seem 

 cause sufficient for even subgeneric division. 



For the purposes of the present review there have been available 

 examples of all the twenty forms here recognized, save two — the newly 

 described D. macrorhyncha and the well-known D. longicauda — com- 

 prising altogether considerably over 100 specimens. In a difl^cult 

 group like Dendrocinda the examination of types is of great value — 

 in many cases of prime importance — and in this we have been fortunate 

 enough to handle the original specimens of D. tyrannina, D. atrirostris, 

 D. 0. lafresnayei, D. meruloides, D. rufo-olivacea, D. castanoptera and 



1 Sclater, Proc. Zool. Soc. Lond., 1859, p. 382. 

 ^ Sclater and Salvin, Ibid., 1868, p. 54. 



