OF EASTERN PENNSYLVANIA. 199 



performed wholly by the female, the male provid- 

 ing her with nourishment. It continues for a period 

 of 1 1 days. 



The young are objects of special regard upon 

 the parental part. Both birds guard them with a 

 jealous care. Their food consists of the diptera 

 before mentioned, spiders, and such larvae as the 

 parent-birds are able to procure from their sur- 

 roundings. They are able to leave the nest in from 

 12 to 13 days, but are still provided for by the 

 parents; the addition of a week to this period pro- 

 duces a marked difference in their development, 

 and fits them for self-maintenance. 



In the fall these birds are gregarious especially 

 in the daytime, but on the approach of night the 

 flocks break up and they retire to their resting- 

 quarters for roosting-purposes. Their departure 

 dates from the 2Oth to the last of September. 



The eggs are oblong in configuration, pointed 

 at one end, and of a pure white color. The average 

 length is .75 of an inch and breadth .54. 



Progne pur pure a, Boie. 



The Purple Martin in some parts of Philadel- 

 phia is not so abundant as formerly. We remem- 

 ber, when a boy, in our neighborhood, it was a very 

 common visitant, and every available house or 

 box, however rude, was taken possession of, on its 

 arrival during the last week of April. This con- 

 dition of affairs continued for several years ; the 

 birds being encouraged to build by the inhabitants 



