TURDUS. 25 



olive. Beneath pale grayish fulvous, rather darker on the flanks, 

 where the color is much as on the back. Belly to crissum white. 

 Chin vs^hite, the feathers streaked centrally with blackish brown ; a 

 whitish region posterior to the streaks. 



Axillars yellowish fulvous, as also to a rather less degree, the in- 

 side of the wings, including the basal portion of inner webs of the 

 quills. Bill and legs horn color, the under mandible paler. 



Length, 8.'?5 ; wing, 5.20 ; tail, 4.30 ; bill to nostril, .57 ; tarsus, 

 1.20 ; middle toe and claw, 1.12 ; claw alone, .30 ; longest primary 

 exceeds the shortest by 1.20 ; second quill intermediate between the 

 6th and 'Tth (.16 longer than the latter). 



This specimen, in color of upper parts, wings and tail, is very 

 similar to Turdus grayi, although readily distinguishable by the 

 white abdomen, darker throat-streaks, etc. 



Turdus leucauchen is distinguishable at a glance from T. assimi- 

 lis, by its colors, almost black above, not fulvous ; light plumbeous 

 ashy beneath, not pale fulvous ; uniform brown of inner webs of 

 quills, and dark axillars, not decidedly paler and fulvous ; greater 

 amount of white on the throat ; yellow bill ; shorter and more 

 rounded wings, etc. 



I have been thus detailed in showing the differences between what 

 I consider characteristic specimens of assimilis and leucauchen, to 

 introduce a series of specimens exactly intermediate between the two, 

 all labelled assimilis: 18,564 from Orizaba, by Dr. Sclater ; 30,648 

 from Guatemala, by Mr. Salvin ; 22,351, Mexico, by Mr. Verreaux. 

 In 22,351, the size, proportion, and color are more like leucauchen; 

 the wings and tail are nearly as dark ; the back, however, is green- 

 ish-olive ; the under parts similar, but paler ; the axillars with a 

 little more fulvous ; the bill is as yellow. In 18,564, the relation- 

 ship to assimilis is shown by a still lighter tinge above, the axillars 

 almost as fulvous as in assimilis. Some dark shaft spots and streaks 

 in the feathers of the breast are indications of a certain degree of 

 immaturity. 



The gradation of these specimens between assimilis, as described 

 above, and leucauchen, is so perfect, that in coloration No. 18,564 

 would, I think, be referred to the former, and 22,35T to the latter. 

 With this, No. 30,648, from Guatemala, recently received from Mr. 

 Salvin, also agrees quite closely — the axillars only being rather more 

 fulvous. 



It is quite possible that these specimens referred to as intermedi- 

 ate forms may, as labelled, all belong to Turdus assimilis ; while 

 22 351 may be another species. In this case I must leave the 



