BIRDS OF SPRINGFIELD, MASS, ETC. 57 



having the faintest possible shade of yelloivish red, but it is 

 barely appreciable, nor is it any more distinct in raising 

 the feathers. There is the faintest possible shade of 

 reddish in the tail and its coverts above, but this is only 

 to be observed on a close examination. This species 

 comes much nearest to Turdus Swainsonii, the Olive- 

 backed Thrush, agreeing with it in the dark greenish olive 

 of the upper surface. This, however, is decidedly darker, 

 and showing a clearer greenish than usual in the other. 

 The absence of any buff on the throat, breast, and sides of 

 the head, and the predominating ashy on the latter, with a 

 white ring instead of a reddish yellow round the eye, are 

 strong points of distinction. The bill appears more 

 slender, and the whole bird is larger. It is barely possible 

 that it may constitute a variety only of T. Siuainsonii; 

 but if so a very strongly marked one." 



Detecting T. " alicice " among specimens I had collected, 

 and many specimens intermediate in color between this 

 form and strongly marked T. Swainsonii, I began to 

 search for some more constant character than color to 

 separate the two forms ; and found by extensive measure- 

 ments that both the largest and the smallest specimens 

 occurred in the form recognized as T. Swainsonii, though 

 some T. alicim were larger than the average of the series. 

 On comparing the proportions of the primaries, some 

 alicice agreed with Siuainsonii while others differed. 

 Comparisons made between the bills, feet and other 

 characters, gave similar results ; while in color the 

 majority of the specimens ranged between those having 

 the greatest amount of reddish-yellow and those in which 

 the buff was scarcely appreciable. The difference in color 

 is merely one of intensity, dependent neither upon sex 

 nor season, possibly upon age, and extends throughout 

 the plumage ; thus those that have the breast of the 

 brightest buff, have also more of this tint pervading the 

 whole plumage, the paler specimens being of the purest 

 dark olive above, without the brownish cast observable in 

 the more rufous individuals. 



Among individuals of Turdus fuscescens, collected the 

 past summer at Springfield, I have detected a dif- 

 ference similar in kind and as great in degree as that 

 separating forms heretofore considered typical respecr 



ESSEX INST. PROCEED. VOL. IV. H. 



