362 



Handbook of Nature-Study 



Willow cone- galls. 

 Photo by Verne Morton. 



enlarges into an oblong room. The caterpillar feeds upon the substance 



of the stem until it attains its growth, 

 something about its future needs. At 

 least it cuts, with its sharp jaws, a little 

 oval door at the upper end of its house 

 and makes an even bevel by widening 

 the opening toward the outside. It 

 then makes a little plug of debris 

 which completely fills the door; but 

 because of the bevel, no intrusive 

 beetle or ant can push it in. Thus 

 the caterpillar changes to a helpless 

 pupa in entire safety ; and when the 

 little moth issues from the pupa skin, 

 all it has to do is to push its head 

 against the door, and out it falls, and 



and then seems to dimly realize 



Spherical gall of goldenrod, 



opened, showing its pros 



perous looking owner. 



Photo by M. v. Slingerland. 



