302 Insects and their Surroundings 



Root-Feeders. — While some insects thus gainliveH- 

 hood for themselves or their young from flowers in the 

 upper air, others burrowing underground devour the 

 roots of plants. Many beetles which feed on leaves 

 have grubs which feed on roots, different parts of the 

 T^^ plant being thus laid under 



Y\\(M contribution by the insect 



*^1i ^i^Vii during the different stages 



J/A of its life-history. While 

 /ft ^'M^^{Am ~^ some grubs, as those of the 

 ■^^^ ''wf/jL « Chafers (fig. 1 1 9) and the 



(fig. 119) 

 Click-beetles, go down to 

 the deeply-branching roots, 

 others, as the maggots of 

 various Flies, eat into the 

 main root just below the 

 surface. Large succulent 

 roots are often riddled by 

 the borings of grubs and 

 this method of feeding is 

 practised even by certain 

 caterpillars which, leaving 

 the usual open leaf-feeding 

 habit of their relations, 

 find shelter as well as food 

 in the tissues of a large 

 tap-root. 



Stem-Borers. — The 



a 



Fig. 163. — Galleries of Bark-beetle 

 {Scolytus rttgulostis, Ratz.). a. 

 Main galleries made by mother 



beetle ; /'. side galleries of grubs ; r i i n-> i 



c. pupal cells. Natural size. From StCmS Of plaUtS alSO aftord 



Ch-cular^Tg (znl'series)! Dlv!"Ent.' shelter and food tO JUSeCtS. 



U.S. Dept. Agr. j^g^ beneath the bark of 



many trees may be found the branching tunnels made 

 by numerous small Beetles and their grubs (fig. l6g) ; 

 while the caterpillars of some Moths, and Sawflies, 

 and the larvse of Longhorn-beetles, make their larger 

 galleries through the heart of the wood. These in- 



