190 
PROCEEDINGS OE THE ACADEMY OF 
The above remarks are made rather with the view of calling attention to the 
facts, than as presenting any solution of the problem. The whole subject is 
one of great interest, and well worthy of extended and careful investigation. 
ACTODROMAS, Kaup. 
Actodromas , Kaup, Sk. Ent. Eur. Thierw. 1829, 55 ; Typus Tringa minuta , Leisl, 
Char. Bill about equal to the head or tarsus, short, straight, very slender, 
somewhat compressed, the tip puactulate, scarcely expanded, acute. Grooves 
on both mandibles, very deep, and extending nearly to the tip. Nostrils situated 
very near the base of the bill. Feathers extending on the lower mandible much 
beyond those on the upper, and half as far as those between the rami. Wings 
long, pointed, first primary usually longest; tertials long, slender, flowing. 
Tail rather long, deeply doubly emarginate, the central feathers much project- 
ing : upper tail coverts moderately long. Tibia bare for more than half the 
length of the tarsus ; the feathers very short, making the exposed portion nearly 
as great. Tarsus equal to the middle toe. Toes long, slender, very narrowly 
margined, entirely free at base. (In typical species the jugulum with an ashy 
or brownish suffusion, thickly streaked ; the rump and upper tail coverts with 
a central blackish field.) 
The genus Actodromas , of Kaup (1829) includes a well marked and very 
natural group of Sandpipers, the quite numerous species of which are very 
closely related borh in form and colors. Its type, from which I have drawn the 
characters in the preceding diagnosis, is the T. minuta , Leisl., a European 
species not occurring in North America, being replaced in that country by the 
Tringa Wilsoni of Nuttall, a very closely allied species, and one with which it 
has been confounded by some authors. The essential characters of the genus 
lie in the short, straight, slender bill, which equals the head or tarsus; the long 
slender toes, the middle equal to the tarsus ; the much denuded tibia with its 
short feathers, and the long, deeply doubly emarginate tail. The peculiar pro- 
portions of bill, tarsus and toe are shared by no other Sandpipers, so far as my 
knowledge extends. The genus is divisible into two well-marked sections ; 
Actodromas proper, with the type T. minuta , having its characters strictly as 
above ; and Heteropygia ,* with the Tringa Bonapartei as type. The latter differs 
in the stouter bill, more expanded at tip; in the much less extent of the en- 
croachment of the feathers on the lower mandible ; in the longer legs, the tarsus 
rather exceeding the middle toe ; in the entire absence of the brownish or ast^ 
suffusion on the jugulum, and ih the white upper tail covers. In this section I 
have placed the Tringa Cooperi of Baird, which is most closely related to the 
A. Bonapartei , and is at any rate an Actodromas rather than a true Tringa. 
The species of the genus now ascertained to inhabit North America are five 
in number: A. maculata , A. minutilla , and the new A. Bairdii, coming under 
Actodromas proper; A. Bonapartei and A. Cooperi , which compose the section 
Heteropygia. The three first of these are so nearly alike in colors, that, their 
form being absolutely identical, size is the chief specific difference. A. macu- 
lata is much the largest, being about nine inches in length ; A. minutilla is very 
small, being less than six inches ; while A. Bairdii is exactly intermediate 
between the two, measuring a little over seven inches. 
The following brief schedule will serve to distinguish the five species, when 
in adult breeding plumage : — 
Actodromas , Kaup. 
A. Jugulum with a brownish or ashy suffusion, thickly streaked. Rump and 
upper tail coverts with a central black field. 
* The name is used with reference to the most conspicuous, though probably not most 
important, feature in which it differs from Actodromas proper. The combination being 
rather an obvious one, the name may have been already employed; in that event I would 
suggest Delopygia with much the same signification. 
[J uly, 
