ARTHROPODA. 



303 



From twenty-two thousand to twenty-four thousand 

 Lepidopterous species have been identified. Some of the 

 most common Butterflies are the swallow-tail Papilio, 

 the white Pieris, the sulphur- 

 yellow ColiaSy 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 Clisiocampa, 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 w T ell 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. 276. — Head of a Caterpillar, from 

 beneath: a, antennae; &, horny jaws; 

 c, thread of silk from the conical fusu- 

 lus, on either side of which are rudi- 

 mentary palpi. 



