ARTHROPODA. 
303 
From twenty-two tliousand to twenty-four thousand 
Lepidopterous species have been identified. Some of the 
most common Butterflies are the swallow-tail PapiUo, 
the white Pieris , the sulphur- 
yellow Colias; the Argynnis , 
with silver spots on the under 
side of the hind wings; the 
Vanessa , with notched wings. 
The Sphinges exhibit little 
variety. They have narrow, 
powerful wings, and are some¬ 
times mistaken for Humming- 
birds. The “ potato -worm ” 
is the caterpillar of a Sphinx. 
The most conspicuous Moths 
are the large and beautiful 
Attacus , distinguished by a 
triangular, transparent spot 
in the centre of the wing; 
the white Bombyx , or “ silk¬ 
worm the reddish-brown Clisiocamjpa , whose larva, “ the 
American Tent-caterpillar,” spreads its web in many an 
apple and cherry tree; the pale, delicate Geometrids; and 
the small but destructive Tineids , represented by the 
Clothes-moth. 
7. Hymenoptera , comprising at least twenty-five thou¬ 
sand species, include the highest, most social, and, we may 
add (if we except the Silk-worm), the most useful, of In¬ 
sects. They have a large head, with compound eyes and 
three ocelli, mouth fitted both for biting and lapping, 
legs formed for locomotion as well as support, and four 
wings equally transparent, and interlocking by small 
hooks during flight. The females are usually provided 
with a sting, or borer. The larvae are footless, helpless 
grubs, and generally nurtured in cells, or nests. Such are 
Fig. 2T6. — Head of a Caterpillar, from 
beneath: a , antennae; b, horny jaws; 
c, thread of silk from the conical fusu- 
lus, on either side of which are rudi¬ 
mentary palpi. 
