IO2 LIFE-HISTORIES OE BIRDS 



Two grades of fibres are readily identified, differ- 

 ing slightly in color and texture; perhaps the pro- 

 ducts of Linum virginianum, and possibly of usi- 

 tatissimum which is occasionally spontaneous in 

 cultivated grounds. The interior is lined with the 



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woolly furze of EriopJwnmi virginicum, and that of 

 various ferns, which render the fabric both cozy 

 and. comfortable. 



To build a nest is the work of three days. Ovipo- 

 sition follows close upon its completion. After 

 the full complement of eggs islaid, incubation im- 

 mediately follows, and continues during a period 

 of 1 1 days. This Warbler is famous for its de- 

 votion to its young and the anxiety which it mani- 

 fests even when the nest is unoccupied; this latter 

 feeling frequently betraying its whereabouts. In 

 this latitude two broods are generally raised in a 

 season, although instances are known, where a 

 third has been successfully raised. The middle of 

 September is fixed upon as the date of their de- 

 parture for more genial climes. 



The eggs of this species are ordinarily five, and 

 occasionally six in number. 1 he}" have a light 

 preen ground-color, and are variously marked with 



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light purple, purplish-brown and lilac dots and 

 blotches. They vary in length from .61 to .70 of 

 an inch, and from .48 to .52 in breadth. 



Dendrceca vlrcns, Baird. 



The Black-throated Green Warbler is rather 

 abundant in Eastern Pennsylvania during its ver- 



