294 ORNITHOLOGICAL EXPLORATIONS. 



with blackish dusky. The light spots on the sides of the neck are very 

 pronounced, while only the ear-coverts are perceptibly light spotted in 

 pallescens. 



It might reasonably have been expected tbat the Wren occurring on 

 the two westernmost islands of the Aleutian chain should belong to the 

 same species as those inhabiting the other ones, viz, T. alascensis. As 

 my friend, Robert Ridgway, however, has already given [l. c.) a careful 

 comparison of the two forms, I shall here only repeat the most strik- 

 ing differences between the adults, viz, that 2)C(llescens has the posterior 

 half of both surfaces distinctly barred with dusky, while in the brighter 

 rusty colored alascensis the whole upi^er surface is quite uniform, ^c^tJl- 

 out any trace of bars, having, besides, a still longer bill.* 



The most interesting feature of the two species is perhaps, however, 

 the fact that the young are even more widely distinct than the adults. 

 The young of alascensis are of the same general bright rusty color as 

 the adults, with the dusky edgings of the feathers on the lower surface 

 very j)ale and indistinct, and the crown of the head is not differently 

 colored from the back. 



It might be thought impossible that the short-billed, dark-colored 

 fumigatus with the very distinct blackish bars should ever have been 

 confounded with the long- billed, bright-colored alascensis^wlnch has no 

 cross-bars whatever on the upper surface, but, nevertheless, we often 

 see the latter quoted as a mere synonym of the former, and Taczan- 

 owski, in 1881, still maintains that fumigatus breeds yearly on the 

 Aleutian Islands (J. f. Orn., 1881, p. 180). For completeness's sake I 

 have therefore appended a second table of dimensions containing the 

 measurements of specimens from the American Aleutians and from 

 Alaska. 



It may be stated here that, although I have examined a series of more 

 than forty specimens, 1 failed to detect any individual presenting inter- 

 mediate characters. The complete isolation of the habitats of the three 

 forms make thfeir iutergradation, a priori, more than improbable. 



In order to give a true idea of the general color of pallescens it may 

 finally be said that it comes very near to pale specimens of T. troglodytes 

 from Central Europe, from which it is distinguished by the pattern of 

 the longest tertiary, the markings on the back, the indistinctness of the 



* Cf. FiNSCH, Abliandl. Nat. Ver. Bremen, III, 1872, p. 31, where he states the re- 

 verse. It is to be remarked, however, that his specimen, from Kodiak, is T. j}acijicm, 

 and NOT T. alaacetibis, as he determined it. 



