158 



NORTH AMERICAN BIRD>?. 



any specimens of T. la/t mnlU, from which it also (litters in longer, straighter, 

 and more subulate bill (tlie gonys slightly ascending). The type sj)ecimen 

 from St. (Jeorge's Island was innnature, and we embr.ice the oi)portunity of 

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

 autumn of 1871 by Mr. Dall from Unalasclika. 



This form l)ears the same relati<jn to T. h}/*nnali>i that Mr/ospiza mia- 

 /((sc/il'ensi.^ does to J/, ladodia ; T. pacijicus, like M. riijina, 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 foinid 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 t(j the 

 Aleuts, lays six eggs. Mr. Dall sul)se(iuently found it quite common at 

 Unalasclika in the summer of 1871. 



Genus CISTOTHORUS, Cahan. 



Cisfofhonis, Cabanis, Mus. Ht-in, IS.'.O, 1851, 77. (Type, Tnxjlodtthji alclhiris.) 

 TiJiimfnihitrs, Cauanis, Mus. Hein. 1850, 1851, 78. (Ty|H', Ccrthln pahisfris.) 

 Thryothoms, Vieillut, Analyse, 1816, according to G. K. Gray. 



Gkn'. Char. Bill about as loiiGr as the head or much 

 short«*r. much compressed, not notched, gently decurved 

 fioni the middle: the jronys sliirhtly 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. Ilind toe 

 longer than or t-qua' to its digit. Wings rather longer 

 than the tail, all the leathers of which ; e nnjch gradu- 

 ated ; the lateral only two thirds the middle. The 

 feathers narrow. Back black, conspicuously streaked 

 with white. 



Cistot/iorus paliistris. 



Of this genus there are two sections, Cutothorns proper and Tthnntodiftrs, 

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

 species present the feature, unii^ue among our Wrens, of white streaks on 

 the back. 



A. Cisto thorns. Pill half length of head. No white superciliary streak. Head 



and rump and back streaked with white. Tail dusky. l>arred with brown. C steUan's. 



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



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



