PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 221 



to be the case in grylle, a feature of which I am unable to speak with 

 absolute certainty, as I have too few young grylle at hand. 



There is another character which holds good, provided only the corre- 

 sponding ages be compared, viz, the extent of the white on the inner 

 web of the primaries. This color ascends from the base like a "wedge" 

 and in the old grylle does not reach further, when looked upon from the 

 lower surface of the wing, than to about the end of the longest under- 

 wlng-coverts, while in mandtii it goes 15-25°^"" beyond these. In the 

 young the white wedge is larger, and consequently reaches beyond the 

 coverts also in grylle., but the corresponding age of mandtii will be found 

 to have them still larger. 



In general coloration the two species do not difl'er materially, except 

 in the winter plumage, which is considerably whiter in mandtii than in 

 true grylle. As full winter plumages of adults of the latter is the weak 

 point of my series I refrain from a detailed comparison, but I have, at 

 home in Norway, handled enough specimens of grylle to state that a 

 true grylle is never found so white at any season as mandtii in adult and 

 full winter garb. 



It will be seen that C. 'mandtii is distinguished at once from its two 

 nearest allies by a white wing-patch unbroken by any black cross-bar^ 

 concealed or not. The latter is a character common to both grylle and 

 columha, which, however, are readily distinguished by the characters 

 given above. But, as indicated, the pattern of the si)eculum also dif- 

 fers materially in the two species. In grylle (Figs. 2, 5) the white tips 

 of the greater wing-coverts are of about the same size in all the feathers, 

 the black cross-bar consequently being of almost equal breadth in the 

 whole extent. In columha (Figs. 1, 4) on the other hand, the white tips 

 decrease towards the edge of the wing, the black bases correspondingly 

 increasing, so that the bar becomes much broader anteriorly, almost 

 assuming the shape of a triangular black wedge.* This is not the only 

 difference, however, for in columha almost all the coverts have got black 

 bases, which often are so pronounced as to form a second visible cross- 

 band on the speculum. 



To complete the comi)arison four tables of measurements are here 

 added. The first shows the superior size of C. columha, and the disj^ro- 

 portionate length of the toes ; second and third prove the slenderness 

 of the bill of mandtii as compared with grylle, and in the fourth the 

 averages are put together to facilitate the comparison. 



* In most young specimens tbe first ones of the greater coverts are entirely black. 



