LEPIDOPTERA. 
69 
wing is distinctly visible. The Lepidoptera have, as a 
rule, six legs, the normal number of all insects, but in 
some of the butterflies the fore legs are either wanting 
or rudimentary. The larvae of the Lepidoptera are 
* popularly termed caterpillars, of various forms and sizes. 
The body contains thirteen segments, the first of which 
forms a strong horny head, provided with biting jaws. 
On the labium there is a slender hollow body, which is 
in communication with two internal glands, whose 
function it is to secrete the substance out of which the 
silky threads are spun. This organ is called the spin¬ 
neret, the value of which will be acknowledged when we 
consider its use in the production of the silk of com¬ 
merce. Many of the Lepidoptera, beautiful as they are 
in their perfect state, are eminently destructive to the 
gardener and the farmer. Every one is familiar with 
the nasty green grub that riddles his cabbages and cauli¬ 
flowers through and through. The enemies that do 
this are the larvae of the “Garden White” butterflies, 
which, like the larvae of most of the Lepidoptera , are 
voracious feeders. They grow rapidly, changing their 
skins frequently. In many species there are two broods 
every year ; others, again, require two years or more 
before they assume the perfect state. In the pupa condi¬ 
tion the creature is inactive : some enclose themselves in 
a silky cocoon, others select the lower surfaces of leaves, 
and roll themselves in, fastening their bodies by silken 
lines; others simply bury themselves in the earth, and 
may often be dug up in the form of dark brown cylin¬ 
drical bodies of various sizes. ' When the insect first 
emerges its wings are soft and crumpled, as may be seen 
by all who have kept silk-worm moths. Fortunately 
