690 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Tyrannus verticaUs, Say, (Arkansas fly-catcher:) 



JTaJ). — Western North America, from the high central plains to the 

 Pacific. 



Arkansas fly-catchers are numerous in the Great Salt Lake Basin, as 

 tbey are among the cottonwoods and bushes that border most of the 

 streams between Salt Lake and Fort Hall. From the 5th to the 28th 

 of June I collected four of their nests; they were placed on willows or 

 cotton woods, from eight to fifteen feet above the ground ; were com- 

 posed of fibrous roots, pieces of dead sage-brush, {artemisia,) dry grass, 

 &c., lined with wool and other soft substances. The first nest that I 

 found is really very beantiful, as well as curious; it is composed of 

 fibrous roots, stalks of dry grass, wool, pieces of sage-brush, with here 

 and there a few leaves, and is lined with wool, fibrous bark, and thread, 

 with a feather occasionally showing itself; there is much wool on the 

 outside and all through the nest, giving it a soft, downy appearance. 

 This beautiful structure contained four cream-colored eggs, spotted 

 with reddish and dark brown, the spots being most numerous near the 

 large end. 



Hah. — Pecos Elver, Texas, and into Mexico table-lands; north to 

 Cheyenne, Wyoming Territory. 



Cheyenne is the only place where I observed this species ; there I 

 secured one specimen. 



Cassin's fly-catcher closely resembles the preceding species, (T. verti- 

 calis,) but is' easily distinguished from it on comparison ; the yellow of 

 the breast is brighter, and the shoulders are more olivaceous ; the bill 

 and feet are larger. The most appreciable character, however, is seen 

 in the tail. In vertlcaUs the whole outer web of the external feather, 

 including tlie shaft, is purely and abruptly yellowish white. In the 

 species now under consideration, the shaft of the outer tail-feather is dark 

 brown, its outer webs and the tips of the other feathers being light brown, 

 with the extreme edges onlj^ being of a tolerably pure yellowish white. 



Sayornis say us, Baird, (Say's fly-catcher:) 



