130 NORTH AMERICAN BIRDS. 



Family TROGLODYTID^. — The Wrens. 



Char. Rictal bristles wanting ; the loral feathers with bristly points ; the frontal 

 feathers generally not reaching to nostrils. Nostrils varied, exposed or not covered by 

 feathers, and generally overhung by a scale-like membrane. Bill usually without notch 

 (except in some Middle American genera). Wings much rounded, about equal to tail, 

 which is graduated. Primaries ten, the first generally about half the second. Basal joint 

 of middle toe usually united to half the basal joint of innei", and the whole of that of the 

 outer, or more. Lateral toes about equal, or the outer a little the longer. Tarsi scutellate. 



The impossibility of defining any large group of animals, so as to separate 

 it stringently and abruptly from all others, is well understood among natu- 

 ralists ; and the Troglodytidce form no exception to the rule. Some bear so 

 close a resemblance to the Mocking Thrushes as to have been combined with 

 them ; while others again exhibit a close approximation to other subfamilies. 

 The general affinities of the family, however, appear to be to the Turdidce, 

 and one of the best characters for separating the two families appears to exist 

 in the structure of the feet. 



In the Turdidce the liasal joint of the outer lateral toe is united to the 

 middle toe, sometimes only a part of it ; and the inner toe is cleft almost to 

 its very base, so as to be opposable to the hind toe, separate from the others. 

 In the Troglodiitida', on the contrary, the inner toe is united by half its basal 

 joint to the middle toe, sometimes by the whole of this joint ; and the second 

 joint of the outer toe enters wholly or partially into this union, instead of 

 the basal joint only. In addition to this character, the open, exposed nos- 

 trils, the usually lengthened bill, the generally e(pial lateral toes, the short 

 rounded wings, the graduated tail, etc., furnish points of distinction. . 



Genera. 



A. Lateral toes very unequal. 



a. Culmen depressed basally, the interval between the nostrils wider than 

 the much compressed anterior half of the bill. Plate on the posterior half 

 of the tarsus continuous. Catherpes. 



h. Culmen compressed basally, the interval between the nostrils narrower 

 than the rather depressed anterior half of the 1)111. Plate on the posteiior 

 half of the tarsus broken into smaller scales. Salpinctes. 



B. Lateral toes equal. 



c. Length about 8 inches. Campylorhynchus. 



d. Length less than 6 inches. 



Bill abruptly decurved or hooked at the tip. Outstretched feet not 



reaching near to end of tail. Thryothorus. 



Tail longer than the wing, the feathers black, variegated terminally 



with whitish Subgenus Thryo manes. 



Tail shorter than the wing, the feathers rusty, not variegated with 

 whitish Subgenus Thry othor.us. 



Bill only gently curved at the tip. Outstretched feet reaching nearly to 



or beyond the end of the tail. 



