172 PROCEEDINGS OP THE ACADEMY OF 



longer than the middle toe and claw. The toes are usually long and slender, 

 more or less margined at the sides, and flattened underneath ; free at the base, 

 or with a very rudimentary membrane, except in Micropalama and Ereunetes. 

 The lateral are nearly equal to the middle, the outer slightly longer than the 

 inner. The hind toe is present, except in Calidris. The claws vary con- 

 siderably in length, acuteness and amount of curvature, but they are always 

 dilated on the inner edge. 



With respect to coloration, the Tringeai of North America, with scarcely the 

 exception of Arquatella maritima, present a general similarity in the pattern 

 and disposal of the markings of most of the parts. The feathers of the upper 

 parts have their centres very dark, and are margined with some shade of red- 

 dish, yellowish, or white, the color being deepest on the scapulars. The 

 primaries are uniformly deep dusky, without spots or bars, and are darkest at 

 the tips and on the outer vanes. The shafts of all are white for some portion, 

 usually the central. The secondaries are ashy-gray, bordered to a greater or 

 less extent with white. The central tail feathers are usually considerably 

 darker than the lateral ; but neither show any approach towards the trans- 

 verse bars so universal among the Scolopacem and Totanince. Any attempt, 

 however, at a generalization of the color of , the under parts seems impossible, 

 since, as will be seen in the diagnoses of the species, they are found of very 

 various patterns and colors. 



The species inhabiting North America are divisible into eight well-marked 

 genera, among which are comprised nearly all the more important ones, 

 though some, such as Eurinorhynchus and Limicola, have no representatives. 

 The most extensive of these, Actodromas, seems to contain two well-marked 

 groups, at least sub-generiually distinct. Each of the others comprises but 

 a single admitted North American species ; and of some, such as Tringa, 

 Arquatella, and Ancylocheilus, but one species is at present known. The cha- 

 racters of the most importance among the TringecB seem to lie in the legs. The 

 proportions of tibia, tarsus and middle toe, and their relations to the bill, 

 readily characterize definitely the groups. They are also the most constant, 

 being subject to very little variation in each species. This is as might be 

 expected, from their radical nature, since the most important and essential 

 character in any group should be the least subject to variation. The bill, on 

 the other hand, differs much in length in the same genus or species ; it reaches 

 its maximum of variation in Ereunetes, and is most constant throughout the 

 genus Actodromas. The wings and tail vary somewhat, but within very 

 narrow limits. 



The North American genera of Tringece may be readily characterized by the 

 proportions of bill, tarsus and toe, without reference to the tail or wings, though 

 these of course furnish additional characters. The following schedule, in which 

 the characters are purposely made as brief as possible, will serve to define 

 the genera as adopted. 



Synopsis of Genera. 



A. Toes with a decided basal web. 



Bill equal to tarsus, both very long ; exposed portion 

 of tibia equal to middle toe, which is not quite 

 two-thirds the tarsus, Micropalama. 



Bill equal to tarsus, both moderate ; tibia exposed 

 for two-thirds the middle toe, which nearly equals 

 the tarsus, Ereunetes. 



B. Toes cleft to the base, or with a very rudimentary membrane. 



I. Bill longer than the tarsus. 



1. Bill straight ; tibia moderately or scarcely at all exposed. 

 Tarsus longer than the middle toe, hind toe present, Tringa. 

 As in Tringa ; hind toe absent, Calidris. 



Tarsus shorter than the middle toe, Arquatella. 



[July, 



