224 NORTH AMERICAN FAUNA 61, FISH AND WILDLIFE SERVICE 



west. The wrens from the Islands of the Four Mountains are 

 described as not typical of petrophilus, but somewhat intermedi- 

 ate between it and seguamensis. However, in the present state of 

 our knowledge, we probably should include the Islands of the 

 Four Mountains in the range of seguamensis. 



Troglodytes troglodytes tanagensis 



After careful study of a series of specimens, tanagensis ap- 

 pears to be slightly less rufescent than petrophilus. In length of 

 bill, it differs significantly, tanagensis having a decidedly longer 

 bill. Measurements of culmen of 12 males and 7 females are as 

 follows : 



Males 14 to 16 mm. ; average, 14.9 mm. 



Females 13.3 to 15.5 mm. ; average, 14.8 mm. 



Since Gabrielson and Lincoln's determination of T. t. segua- 

 mensis, we must confine the range of tanagensis to Tanaga and 

 the immediately adjacent islands. 



Troglodytes troglodytes kiskensis 



This wren is paler, but more tawny, than meligerus. It is also 

 more tawny than tanagensis. In length of culmen, it appears to 

 average greater than either of the other two. Measurements of 

 culmen, in millimeters, of 8 males and 8 females are as follows : 



Males 14.5 to 16 mm. ; average, 15.6 mm. 



Females 14 to 17 mm. ; average, 15.2 mm. 



This wren occupies the Rat Islands group, from Kiska to 

 Amchitka. There *are specimens from Kiska, Little Kiska, 

 Davidof, Little Sitkin, Semisopochnoi, and Amchitka; and there 

 are three specimens from Ogliuga Island, in the Andreanof 

 group — supposedly in the range of tanagensis, which appeared 

 referable to kiskensis. 



Troglodytes troglodytes meligerus 



The wrens of the Aleutian chain fall into two groups that may 

 be distinguished pretty well at the extremes of the total range. 

 The wrens of the westernmost islands, and we may include the 

 Commander Islands, show a marked tendency toward a dusky, 

 grayish cast, while those of the eastern Aleutians, including 

 alascensis, of the Pribilofs, are more rufescent. 



T. t. meligerus is quite similar to T. t. pallescens of the Com- 

 mander Islands, sharing with that form the general duskiness 



