114 PROCEEDINGS OF THE ACADEMY OF [1896. 



In cases where there is an appreciable difference in the time of 

 shedding the different pairs of tail-feathers, it is the general rule 

 that the outermost pair is the last to be shed, and birds are not 

 infrequently found with the new central pair of tail-feathers half- 

 grown, while the old outermost pair is still retained (PI. V, fig. 2). 

 The swallows are especially good examples of this, as the molt of 

 the tail in this group seems to be very gradual (PI. IV, fig. 4). 



In Quiscahis and some other birds the central pair is the last to 

 be molted, all the others having nearly completed their growth 

 before the old middle feathers are shed. 



In the Woodpeckers the molt begins with the pair next to the 

 middle' and extends outward while the central pair is the last to 

 be shed (PI. V, fig. 1). 



In this family the tail has a particular function, — i. e. in climb- 

 ing; hence the slow molt, as the birds would be at a great disadvan- 

 tage if the whole tail was lost at once. The central pair of feathers 

 are of particular importance, and the old ones are, therefore, 

 retained until the new quills of the next pair have become suffi- 

 ciently developed to temporarily take their place during their own 

 renewal. 



The tail-feathers generally correspond with the primaries and 

 secondaries in the number of molts which they undergo during the 

 year, but in some cases where there is a spring molt of the body 

 feathers, together with the tertials, there is also a complete molt of 

 the tail, while the primaries and secondaries are not renewed. This 

 takes place — in certain individuals at least — in the Sharp-tailed 

 Finch, Ammodramus caudacutus. 



Another peculiarity of the tail-feathers is their renewal at times 

 other than those of regular molt, when they have been lost through 

 accident. This does not occur in the wing feathers so far as I am 

 aware. Perhaps owing to the fact that the wing feathers are so 

 much more firmly rooted than any of the other feathers, they are 

 rarely if ever lost through accident, and hence the necessity for 

 renewal does not arise ; while the tail-feathers on other hand are 

 the most frequently lost of any of the feathers, for, owing to their 

 position, they are often caught and pulled out by beasts or birds 

 of prey. 



Having considered the order of the molt in the body-feathers, wing 

 and tail separately, it remains to consider the relative time of molt 



^ In one specimen of Dryohaleti puhescens examined, this pair and the next 

 outer pair were shed simultaneously. 



