476 
LEPIDOPTERA. 
Some of them have sixteen legs, others have only fourteen. 
The latter creep very much like the span-worms, hut are 
more active and quick in their motions. Most of them 
live exposed upon or under the leaves of plants, and, when 
they come to their full growth, they enclose themselves 
in cocoons formed of folded leaves thinly lined with silk, 
in which they undergo their transformations. Some kinds 
QHydrocampa and Petropliild) live in the water upon aquatic 
plants, and secure themselves in cylindrical leafy cases, fitted 
to cover the whole of the body except the head and six fore 
legs, and made air-tight. These cases prevent the water 
from getting into the lateral breathing-holes of the cater¬ 
pillars, and contain a sufficient quantity of air for them to 
breathe; and, with them, they can easily move about under 
the surface, upon the plants which serve them for food. 
Some of the aquatic kinds do not make these air-tight cases, 
for they do not need them, as they breathe through fringed 
gills, placed along the sides of their bodies. Thus we see 
that even aquatic plants are inhabited by peculiar tribes of 
insects, which keep in check their redundant vegetation, and 
which are fitted, by extraordinary and curious contrivances, 
for the element wherein they are appointed to live. These 
aquatic insects stand on the limits of the order, and con¬ 
nect the Lepidoptera with the Neuroptera^ by means of the 
May-flies {Pliryganeadce) belonging to the latter order. 
Those caterpillars of the Pyralides that have only fourteen 
legs may be called Herminians (HERMixiADiE), after the 
principal genus in the group. The hop-vine is often infested 
by great numbers of these caterpillars. They eat large holes 
in the leaves, and thereby sometimes greatly injure the plant. 
Caterpillars of this kind have also been observed on the 
hop in Europe, from whence ours may have been intro¬ 
duced ; but until specimens from Europe and this country 
are compared together, in all their states, it will be Avell 
to consider the latter as distinct. Our hop-vine caterpillars 
9 re false-loopers, bending up the back a little when they 
