THE OAK. 



45 



eats its way out through a great portion of the 

 solid substance of the gall. 



The habitation of all the parasitic insects 

 hitherto mentioned is formed out of the pulpy 

 substance of the tree : one, however, which is 

 not uncommon, and is called the Artichoke -gall, 

 is an irregular development of the bud, and con- 

 sists of a number of leafy scales overlapping each 

 other. At first sight it might almost be taken for 

 a young cone ; but on dissection is found, like 

 other galls, to contain insects in various stages 

 of their growth, according to the season. 



Another singular appendage of the leaf is the 

 Oak-spangle, a fiat circular disc, attached by its 

 central point to the under surface of the leaf. 

 The inner side is smooth; the outer red, hairy, 

 and fringed. Each of these contains a single in- 

 sect, which retains its habitation until March, 

 long after the leaves have fallen to the ground. 



OAK-SPANGLES. 



