540 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY — GENERAL REPORT. 



Sub-Family ICTERINAE. 



Ch. — Bill slender, elongated, as long as the head, generally a little decurved, and very acute. Tarsi not longer than the 

 middle toe, nor than the head ; claws short, much curved ; outer lateral toe a little longer than the inner, reaching a little 

 beyond base of middle toe. Feet adapted for perching. Tail rounded or graduated. Prevailing colors yellow or orange, and 

 black. 



The species of this sub-family are all as strikingly characterized by diversity and brilliancy 

 of plumage as the others are (with few exceptions) for their uniform sombre black, scarcely 

 relieved by other colors In certain respects there is a decided resemblance to some of the Sylvi- 

 colidae, from which, in fact, the much larger size is, in some cases, the chief apparent distinc- 

 tion. 



In studying the North American Orioles I have found it exceedingly difficult to arrange them 

 in any sharply defined sections, as whatever characters be taken as the basis of classification, the 

 other features, will not correspond. Thus, species with the bill of the same proportions and 

 amount of curvature differ in the shape and graduation of the tail, while tails of the same form 

 are accompanied by entirely dissimilar bills and wings. The bill is sometimes much attenuated 

 and decurved, as in /. cucullatus, while in melanocephalus and haltimore it is stouter and straighter. 

 The tail is usually much graduated ; in I. haltimore and bullocJci it is only moderately rounded. 

 These last mentioned species constitute the genus Yphantes. Many of the species have a naked 

 space round the eye ; very evident in 1. vulgaris, less so in melanocephalus. I. vulgaris is 

 peculiar in having the feathers of the throat pointed and lanceolate as in the ravens. 



In view of the difiiculties attendant upon the definition of subordinate groups among the 

 United States Icterinae, I propose to consider them all under the single genus Icterus, leaving 

 it for some one with a fuller series of specimens at his command to establish satisfactory divisions 

 into genera. 



The colors of the Orioles are chiefly black and yellow, or orange, the wing sometimes marked 

 with white. The females are much duller in plumage, and the young male usually remains in 

 immature dress till the third year. In^all the North American species the rump is of the same 

 color with the belly ; the chin, throat, and tail, black. 



The following synopsis may serve to distinguish the species as far as color is concerned. 



A. Head and neck all round black. 



Back black, se^iarated from that of the head by the color of the belly. 



Orange, yellow, and black. Greater wing coverts and edges of secondaries, white ; lesser 

 coverts and tail black, the latter white at the extreme base /. vulgaris. 



Back greenish yellow ; wings and tail black ; the lesser coverts yellow. Colors yellow and 

 black. 



Greater coverts and quills edged with white 7. audubonii. 



No white edges whatever on the wings and tail. Smaller size and stouter bill. 



I. melanocephalus. 

 Back black, continuous with that of the neck. Lesser coverts like the belly. 



Yellowish orange and black. Entire tail, with ends of upper and lower coverts, black. 

 No white on the wings /. wagleri. 



Yellow and black. Edges of greater coverts and of quills white. Tail yellow ; middle 

 feathers and terminal third, with all of upper and under coverts, h\a,ck...I.pari8orum. 



