190 PROCEEDINGS OP 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. 



Actodromns, 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 puoctulate, scarcely expanded, acute. Grooves 

 ou 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 t lie- 

 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 geuus is divisible into two well-marked sections : 

 Actodromas proper, with the type T. minuta, having its characters strictly as 

 above ; and Heleropygia* with the Tringa Bonapartei as type. The latter differs 

 in the stouter bill, more expanded at lip; 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 ashy 

 suffusion on the jugulum, and in 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. metadata, 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 exact'y 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, ihough probably not most 

 important, feature in which it differs from ActodTcrmas 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. 



[July, 



