226 PALMER, The Maryland Vellow-throat. ak 
Differences. 
The differences between typical specimens of the three eastern 
forms are quite strong. ‘True ¢richas (Maryland) is a very small 
bird with a slender, short bill, restricted black facial area and pale 
colors in spring. It has a short, well-rounded wing in which 
there is little difference between the 3rd, 4th and 5th primaries, 
while the rst is decidedly much shorter than the 6th. The form- 
ula! of length is usually 3-4~-2-5-6-1—7-8, sometimes 4-3-5-—2-6 
—1—7-8, rarely 4—5—3-2-6-1—7-8. In immature birds and in the 
most unworn spring specimens the formula is 4-3-5—2-6—7-1-8, 
the differences between the rst and 7th being slight. The inner 
primaries wear faster than the outer, being weaker. Spring 
specimens taken about Washington, D. C., are always well worn 
and pale, contrasting strongly with the less worn and _ brighter 
specimens of dbrachidactyla taken at the same time and place. 
Nine spring males range in size: wings, 50-54 mm.; tails, 
48.5-52 mm.; culmens, 9-10 mm.; tarsi, 21-23 mm. Ten 
females: wings, 47-51 mm.; tails, 46-48.5 mm.; culmens, 9.5-11 
mm.; tarsi, r1g-21 mm. The females sometimes lack entirely the 
yellow of the throat and breast which is never as extensive and 
as strong as in the other forms. 
In its well rounded wing roscoe agrees with ¢richas but differ- 
ence in length of the feathers makes a different formula. The 
3rd, 4th and 5th are nearly equal, and a slightly wider interval 
separates the 2nd and 3rd, while the rst is considerably shorter 
than the 2nd, as in ¢réchas. But the inner primaries are longer, 
so that the formula is 4-5—3-2—-6—7-8-1. Wearing takes place 
more rapidly on the inner primaries so as to result in the usual 
formula on worn individuals of 4—3-5—2-6-1-7-8. It is a much 
larger bird with a longer, stouter bill and tail, and a strong brown- 
ish tinge even in worn summer specimens. ‘The wide forehead 
black and the ochraceous tinge of the yellow of the underparts 
are characteristic of thisform. Thus ¢vzchas and roscoe agree well 
in the wing pattern but differ greatly in size and color. 
‘The outermost primary is here for convenience considered the first : the 
first number represents the longest feather, the last the shortest. 
