308 SYSTEMATIC AKRANGEMENT 



appendage at their base. The lower edge of each 

 of these plates is finely toothed throughout its whole 

 extent, the teeth directed backwards, and at the 

 same time turned a little outwards. The surface 

 of these plates is very smooth internally, hut the 

 outer side is partly covered with very closely placed 

 oblique strise and elevated lines. When the in- 

 strument is put in motion on the surface of a leaf, 

 or on a twig, the small teeth act as a saw, while 

 the lateral ridges perform the office of a file or rasp. 

 By this means a suitable opening is soon formed for 

 receiving the eggs. These are sometimes placed 

 within the woody substance of the branches of 

 shrubs, but more commonly they are attached to 

 the leaves. An instance of the former sort is ob- 

 served in the Rose Saw-fly, (Hylotonna Rosce,} and 

 a familiar example of the latter in the species which 

 infests gooseberry and currant bushes, which ar- 

 ranges its eggs in rows along the mid rib and 

 principal nervures of the leaves. In all cases the 

 eggs are not long in being hatched ; and the young 

 larveB generally find their appropriate food in the 

 leaves of the plant on which the provident mother 

 had placed them. 



From the general resemblance these larvae bear 

 to the caterpillars of butterflies and moths, they are 

 called false caterpillars, as the word caterpillar ought 

 to be restricted to the former. A very slight ex- 

 amination is sufficient to enable one to discover de- 

 cided marks of distinction between them. The true 

 caterpillars the larvse of Lepidoptera have never 



