308 SYSTEMATIO ARRANGEMENT 
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 striae 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, ( Hylotoma 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 
larvae 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 larvae of Lepidoptera — have never 
