34 
ALLEN’S naturalist’s LIBRARY. 
with an array of pen-feathers. As soon as these have reached 
a development which makes the youngster look like a sma 1 
Young Kingfisher, to show the pen-feathers. 
Porcupine, the sheath breaks and falls off, and the feathers 
cover the body at once. 
THE SWIFTS. SUB-ORDER CYPSELI. 
The Swifts and the Night- Jars have generally been associated 
in recent classifications of birds with the Humming-Birds, as 
forming an Order Machrochires. The association of the Swifts 
