TROGLODYTID^E — THE WRENS. 



141 



Genus THRYOTHORUS, Vieill. 



Tliryothorus, ViEii.r.oT, Analyse, 181 G, 45. (Type, Troglodytes arundiimceus, "Troglodyte 

 des lioseaux," Vieill. Ois. Am. Sept. II, 1807, 55 = Sylvia ludoviciana, Lath.) 



Ge\. Char. Bill compressed, rather slender ; height about one fourth the length above. 

 Culmen and commissure gently curved throughout; gonys straight; tip very obsoletely 

 notched. Nostrils in the lower edge of anterior 

 extremity of the nasal groove, narrowly elliptical, 

 overhung by a stiff scale-like roof of the thickened 

 membrane of the upper part of the nasal groove, the 

 crescentic edge rounded. The septum of nostrils 

 imperforate; the posterior part of the nasal cavity 

 with a short septum projecting into it parallel with 

 the central, not perpendicular as in Microcerculus. 

 Wings and tail about equal, the latter moderately 

 rounded ; the first primary more than half the 

 second, about half the longest. Tarsi rather short, 

 scarcely exceeding middle toe. Anterior scutellie 

 distinct, rest of each side of tarsi in a continuous plate. 



Tliryothorus lui/oricicianus. 



Lateral toes equal. 



The diagnoses of the North American species are as follows : — 



Species and Varieties. 



CoiMMON Characters. Head above, and back, of much the same color. Cris- 

 sum barred transversely ; rest of under parts plain. Upper tail-coverts and ex- 

 posed surface of wings barred. Iris hazel. Nest in holes or with an arched 

 covering. Eggs reddish-white, spotted with red and purple. 



a. Tliryothorus. 

 T. ludovicianus. Tail-feathers reddish-brown, barred with black. Greater 

 wing-coverts spotted with whitish. 



Beneath yellow-whitish, washed occasionally with rusty. Sides plain. 

 Bill from nostril, .45. Length, G.OO. Hah. Eastern Province United 

 States ■..-...... var. I udov i cian u s. 



Beneath rufous; lighter on throat and along median line. Sides 

 obsoletely barred with dusky. Bill from nostril, .56. Length, 5.25. 

 Hah. Lower Rio Grande var. berlandieri. 



h. Telmatodytes. 

 T. bewickii. Tail-feathers, except central, black ; the exposed surface and 

 tips only varied with white. Length, 5.50. 



Above dark rufous-brown ; beneath plumbeous-white ; flanks tinged 

 with brown. Rump and exposed secondaries distinctly banded. Quills 

 and middle tail-feathers brownish-black. Length from nostril, .39; 

 along gape, .70. Hab. Eastern Province United States. var. heivickH. 



Above ashy-brown ; beneath, including flanks, clear white ; rump 

 ashy, and, like secondaries, very obsoletely barred. Quills and middle 

 tail-feathers grayish-brown. Hah. Southern border of United States, 



into Mexico var. leucogaster. 



Colors intermediate between the two last. Bill longer, from nostril, 

 .50, from gape, .81. Hah. Pacific Province .... var. spilurus . 



