FOOD OF 1NSF.CTS. 383 



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 {Sesia apiformis, &c.), 

 others the alburnum [Semasia Wceherana), others the 

 exuding resinous or other excretions {Scoparia Resi- 

 nella), a third class the pith {Xanthia Ochraccago), and 

 a fourth penetrate into the heart of the solid wood {Pri- 

 onus. Lamia, Ceramhyx, &c). 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 

 parenchyma, never touching the cuticle (subcutaneous 

 Tinecs, Gracillaria F) others only the lower surface of 

 the leaf (many Toririces), while a fourth description de- 

 vour the whole substance of the leaf (most Lcpidoplera). 

 And of the flower- feeders, while some eat the very pe- 

 tals {Cucidlia Verhasci, Xylina lAnarice, &c.), others in 

 their perfect state select the pollen which swells the an- 

 thers (bees, LepturcCy and Mordella), and a still larger 

 class of these the honey secreted in the nectaries (most 

 of the Lepidoptera, Hijrtienoptera, and Diptera). 



Nor are insects confined to vegetables in their recent 



