158 



NORTH AMERICAN BIRDS. 



any specimens of T. hyrmalis, from which it also differs in longer, straighter, 

 and more subulate bill (the gonys slightly ascending). The type specimen 

 from St. George's Island was immature, and we embrace the opportunity of 

 giving the description of an adult sent down with several others in the 

 autumn of 1871 by Mr. Dall from Unalaschka. 



This form bears the same relation to T. lujcmalis tliat Melospiza una- 

 laschkensis does to M. melodia ; T. 'pacificus, like M. riifina, being an inter- 

 mediate form. 



Habits. Of this new variety, the Alaska Wren, but little is as yet 

 known as to its personal history. Mr. Dall states that it is found in abun- 

 dance all the year round on St. George's Island, and that it breeds in May, 

 building a nest of moss in the crevices of the rocks, and, according to the 

 Aleuts, lays six eggs. Mr. Dall subsequently found it quite common at 

 Unalaschka in the summer of 1871. 



Genus CISTOTHORUS, Caban. 



Cistothorus, Cabanis, Mus. Hein. 1850, 1851, 77. (Type, Troglodytes stellaris.) 

 Tehnatodytes, Cabanis, Mus. Hein. 1850, 1851, 78. (Type, Certhia palustris.) 

 Thryotliorus, Vieillot, Analyse, 1816, according to G. K. Gray. 



Gen. Char. Bill about as long as the head or much 

 shorter, much compressed, not notched, gently decui-ved 

 from the middle ; the gonys slightly concave or straight. 

 Toes reaching to the end of the tail. Tarsus longer than 

 the middle toe. Hind toe longer than the lateral, shorter 

 than the middle. Lateral toes about equal. Hind toe 

 longer than or equal to its digit. Wings rather longer 

 than the tail, all the feathers of which are much gradu- 

 ated ; the lateral only two thirds the middle. The 

 feathers narrow. Back black, conspicuously streaked 

 with white. 



Cistothorus palustris. 



Of this genus there are two sections, Cistothorus proper and Telmatodytes, 

 the diagnoses of which have already been given. The two North American 

 species present the feature, unique among our Wrens, of white streaks on 

 the back. 



A. Cistothorus. Bill half length of head. No white superciliary streak. Head 



and rump and back streaked with white. Tail dusk}^, barred with brown. C. stellaris. 



B. Telmatodytes. Bill length of head. A white superciliary stripe. Back 



alone streaked with white. Tail-feathers black, barred with whitish . C- palustris. 



