158 



NORTH AMERICAN BIRDS. 



any specimens of T. hi/cmalis, from which it also differs in longer, straighter, 

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

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

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

 autunm of 1871 by j\Ir. Dall Irom Unalaschka. 



This form bears the same relation to T. hyanalis tliat Mdosjnza una- 

 laschkensis does to J£ mdodia ; T. jMcificus, like M. rufina, being an inter- 

 mediate form. 



HABiTa. (_)f 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 tliat it breeds in j\Iay, 

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

 Aleuts, lays sLx eggs. Mr. Dall subsequently foimd it quite common at 

 Unalaschka in the summer of 1871. 



Geni s CISTOTHORUS, Caban. 



CistothoruD, Cabanis, Mus. Heiii. ISoO, 1851, 77. (Type, Troglodytes stcllaris.) 

 Tdmatodytes, Cabanis, Mus. Hein. 1850, 1851, 78. (Type, Certhia paluslris.) 

 Thryothoms, Vieillot, Analyse, 1816, according to G. R. Gray. 



Gen". Cii.vR. Bill aliout as long a.s tlu' head or inueli 

 sliort(M\ much comprcs.sed, not notched, gently decurved 

 from the middle ; the gonys sliglitly concave or .straight. 

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

 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 tlie middle. The 

 feathers narrow. Back black, con.spicuously streaked 

 Ciitothorus paluslris. with white. 



Of this genus there are two sections, Cvitoihorus proper nnd Tihtuitoilijh's, 

 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 



ami niiiip :iiid Kack streaked with wliite. Tail dusky, barred with brown. C. stdlarh. 



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



alone streaked with white. Tail-feathers black, barred with whitish . C. yahislr'u. 



