254 Insect Architecture. 



the two external membranes. Let any one try with the 

 nicest dissecting instruments to separate the two plates of 

 a rose-leaf, and he will find it impossible to proceed far 

 without tearing one or other. The caterpillar goes still 

 further in minute nicety; for it may be remarked, that 

 its track can only be seen on the upper, and not on the 

 under surface of the leaf, proving that it eats as it pro- 

 ceeds only half the thickness of the pulp, or that portion of 

 it which belongs to the upper membrane of the leaf. 



We have found this little miner on almost every sort of 

 rose-tree, both wild and cultivated, including the sweet-briar, 

 in which, the leaf being very small, it requires nearly the 

 whole parenchyma to feed one caterpillar. They seem, how- 

 ever, to prefer the foreign monthly rose to any of our native 

 species, and there are few trees of this where they may not 

 be discovered. 



Leaf of the Dew-berry Bramble (Rubus cceoiws). mined by Caterpillars. 



Tunnels very analogous to the preceding may be found 

 upon the common bramble (Eubus fruticosus) ; and on the 

 holly, early in spring, one which is in form of an irregular 

 whitish blotch. But in the former case, the little miner 

 seems to proceed more regularly, always, when newly 

 hatched, making directly for the circumference, upon or near 

 which also the mother -moth deposits her egg, and winding 

 along for half the extent of the leaf close upon the edge, 

 following, in some cases, the very indentations formed by 

 the terminating nervures. 



