FOOD OF INSECTS. 383 



is of little use either to mankind or the larger animals, 

 but you will not doubt its importance to the class of in- 

 sects, when told that at least thirty distinct species feed 

 upon it. But this is not all. The larger herbivorous 

 animals are confined to a foliaceous or farinaceous diet. 

 They can subsist on no other part of a plant than its 

 leaves and seeds, either in a recent or dried state, with 

 the addition sometimes of the tender twigs or bark- 

 Not so the insect race ; to different tribes of which every 

 part of a plant supplies appropriate food. Some attack 

 its roots ; others select the trunk and branches ; a third 

 class feed upon the leaves ; a fourth with yet more deli- 

 cate appetite prefer the flowers ; and a fifth the fruit or 

 seeds. Even still further selection takes place. Of those 

 which feed upon the roots, stem, and branches, of vege- 

 tables, some larvae eat only the bark (Sjihinx apifonnis, 

 &c), others the alburnum {Tortrix TVbeberana), others 

 the exuding resinous or other excretions {Tinea Mesi- 

 nella), a third class the pith (Noctua Ochraceago, Lep. 

 Brit.), and a fourth penetrate into the heart of the solid 

 wood (Cerambyces). Of those which prefer the leaves, 

 some taste nothing but the sap which fills their veins 

 {Aphides in all their states), others eat only the paren- 

 chyma, never touching the cuticle (subcutaneous TinecE\ 

 others only the lower surface of the leaf (many Tortrices\ 

 while a fourth description devour the whole substance of 

 the leaf (most Lepidoptera). And of the flower-feeders, 

 while some eat the very petals [Noctua Verbasci, Linarice, 

 &c), others in their perfect state select the pollen which 

 swells the anthers (bees, Lepturce, and Mordella:), and a 

 still larger class of these the honey secreted in the 



