A WOOLLY FLOCK 237 
Harris, is so buoyant as to enable the insect to be 
borne upon the breeze from tree to tree. To 
this resource he attributes the spread of the wing- 
less apple-lice species. But it would take a stiff 
breeze thus to waft the body of our plump dweller 
on the alder, unless, indeed, in his younger days. 
