452 BLUE BIRD. 



is 2 inches 1 twelfth long, its average width I5 twelfth ; that of the 

 proventriculus 2^ twelfths. The stomach is elliptical, compressed, 7 

 twelfths long, 5^ twelfths in breadth ; its lateral muscles rather strong, 

 the tendons large ; the epithelium reddish -brown, longitudinally rugous. 

 The intestine is 6 inches long, 1^ twelfth in width ; the coeca 1 twelfth 

 long, i twelfth wide, 9 twelfths from the extremity. 



The trachea is 1^ inch long, scarcely 1 twelfth in breadth, consi- 

 derably flattened, firm, its rings 75, with 2 dimidiate rings ; the mus- 

 cles as usual in the Thrushes, Warblers, and Larks ; the bronchi 

 with 18 half rings. There is a very slender salivary gland on each 

 'side. 



BLUE BIRD. 



Sylvia Sialis, Lath. 



PLATE CXIII. Vol. II. p. 84. 



I HAVE not received any intimation of the occurrence of this inte- 

 resting bird to the west of the Rocky Mountains, although it was ob- 

 served by Dr Townsend on the head waters of the Missouri. Dr Rich- 

 ardson mentions it as being found in summer to the eastward of the 

 Rocky Mountains, up to the 48th parallel of latitude, beyond which 

 none were seen by the members of the expedition. I found it abundant 

 and breeding in the Texas. The eggs measure seven and a half eighths 

 of an inch in length, five-eighths and three-fourths in breadth, and are 

 rather more bulky than is usual in birds of this family. In the United 

 States, when in an uncultivated district, it forms its nest in the hollow 

 or hole of a tree. 



In a male preserved in spirits, the roof of the mouth is flat, and 

 similar to that of the Thrushes ; the tongue triangular, deeply emar- 

 ginate and papillate at the base, very thin, flat above, horny towards 



