1898.] NATURAL SCIENCES OF PHILADELPHIA. 85 



67. Vireo flavifrons. Yellow-throated Vireo. 



Not uncommon, being frequently met with during the breeding 

 season, especially in the deep woods. 



68. Vireo solitarius. Blue-headed Vireo. 



Common in the deep forests throughout the greater portion of 

 the county, one or more pairs being usually met with in all 

 the larger pieces of woodland. Two adults with young just out 

 of the nest and nut yet able to fly were observed July 8, 1896, 

 about two miles south of Springville. 



69. Mniotilta varia. Black and White Warbler. 



Tolerably common in second growth woods and clearings. 



70. Compsothlypis americana. Parula Warbler. 



Not uncommon, and several times met with in woods where there 

 is apparently no usnea moss. It would be interesting to know what 

 the bird constructs its nest of in such localities. 



71. Dendroica aestiva. Yellow Warbler. 

 Common throughout the open country. 



72. Dendroica caerulescens. Black-throated Blue Warbler. 



Abundant and generally distributed in the deep hemlock woods, 

 being, perhaps, the commonest representative of its genus. 



73. Dendroica maculosa. Magnolia Warbler. 



Another very common species, almost as plentiful as the preced- 

 ing, but like it coufined to the deep hemlock woods. 



74. Dendroica pennsylvanica. Chestnut-sided Warbler. 



Common, but confined to the clearings and tracts of 'scrub.' A 

 nest together with the brood of young birds was discovered June 27, 

 1896, in a small orchard within a few yards of the house. 



75. Dendroica blackburniae. Blackburnian Warbler. 



Abundant wherever there is a thick growth of hemlock. It 

 would be hard to say whether this species or D. caerulescens is the 

 more plentiful, for as Dr. Dwight remarks, there are " places where 

 both might almost be said to swarm." 



76. Dendroica virens. Black-throated Green Warbler. 



Also abundant in the deep hemlock forests, but hardly as plenti- 

 ful as the preceding species. 



77. Seiurus aurocapillus. Oven-bird. 

 Abundant everywhere. 



