18 



MK. P. H. BAHR ON THE 



[Jan. 15, 



to which I firmly bound it with cotton and inserted the feathers 

 into a cork at the end of a stick some six inches long. A hole is 

 bored at the other end of the stick and a long stiing attached. 

 This is whirled round the observer's head and a tyj)ical bleat is 

 produced. The second outer tail-feathers (sixth pair) produce a 

 fainter sound, though this varies much in individual tails, the 

 others make no sound at all. 



Text-fig-. 4. 



tJf' 



Varieties of outer tail-fesitliers of GcdUnago coelestis. (Natural size.) 



