10 PROCEEDINGS OF THE ACADEMY OP 



The most reliable peculiarity of cinerascens is the contour of 

 the rufous on the rectrices. In all other Myiarchi examined the 

 rufous, no matter how broad or how narrow, is straight-edged 

 against the fuscous from base to tip; but in cinerascens it occu- 

 pies the whole inner web for about -| or the length of the 

 feather, and then bends inward to give way to fuscous that conse- 

 quently possesses most or all of the tip of the feather. It is a 

 curiously slight matter to be so constant as it appears ; and it is 

 not absolutely invariable. Thus, in U. S. specimens, constituting 

 the best-marked examples, the rufous is commonly altogether shut 

 off from the end of the feathers, while in Tehuantepec skins the 

 rufous gains the very tip, being but little encroached upon by the 

 fuscous. However, even in these specimens, which barely escape 

 being troublesome, the peculiar pattern is exhibited. But in no 

 case do other than adult birds show the peculiarity ; e. g., in No. 

 1595, Mus. E. C, shot from the nest in Arizona, the wings and 

 tail are nearly as rufous as in validus! the margins of all the 

 remiges and upper wing coverts, and all the tail feathers are 

 rufous, the rectrices having each merely a narrow shaft-line of 

 fuscous; the upper parts are grayish-brown, without olive; the 

 cap warm pure brown, the belly white, slashed with yellow. 



But cinerascens has other marks, none of them infallible, all of 

 them nevertheless useful. It is the palest Myiarchus of all. The 

 upper parts are gray, merely suffused with olive, and browner on 

 the head; the gular ash is gray and hoary; the belly very pale 

 yellow, or yellowish-white, without sharp demarcation from the 

 hoary on the breast; the margining of the inner secondaries and 

 wing coverts is grayish-white (not yellowish nor ochrey-white) ; 

 the bill is almost perfectly black. My palest birds come from the 

 United States deserts and from Cape St. Lucas; here the olive 

 above and yellow below are barely appreciable. Tehuantepec and 

 Mazatlan birds are the brightest ; here the yellow is almost as 

 pure as in crinitus (and these, it will be remembered, are the ones 

 with rather 'dubious tail-coloration). 



There is nothing diagnostic in the size or shape of this bird, 

 but several tangible characters are usually exhibited. Compared 

 with crinitus, the bill has a constricted, somewhat more terete 

 shape ; probably it is rarely if ever quite half as wide as long op- 

 posite the nostrils. The tarsi average longer, frequently touching 

 .90. The wings average a little shorter relatively, and the tail a 



[July 2, 



