ORDER LEPIDOPTERA. 145 



the body. The third is drawn out by the two fore feet, 

 which are three-jointed and end in a single claw. The legs 

 on the hind body, sometimes called prop-legs, are fleshy, 

 not jointed, and end in a crown of hooks which curve out- 

 ward, enabling the caterpillar to firmly grasp the edge of 

 the leaf or twig of its food-plant. 



Most caterpillars are more or less hairy or spiny, ren- 

 dering them, when especially so, disagreeable to birds; be- 

 sides this, they are bright-colored, so that birds readily rec- 

 ognize them and waste no time over them, but search for 

 the common green smooth-bodied ones, which are, however, 

 so difficult of detection by the birds that plenty are left to 

 become moths or butterflies. Certain caterpillars, as the 

 currant-worm, though smooth-bodied, are brightly spotted; 

 these, however, the birds find, have a disagreeable taste. 

 The bright colors are thus danger-signals, hung out to warn 

 the birds. 



We will now suppose that the caterpillar has got its 

 growth, and is about to change to a chrysalis. When fully 

 fed the caterpillar stops eating, and in a day or two throws 

 off the caterpillar's skin and becomes a pupa or chrysalis. 

 The latter word is derived from the Greek, meaning golden, 

 in allusion to the golden spots which adorn the chrysalids of 

 some butterflies. Our Turuus caterpillar, before pupation, 

 as the act of becoming a pupa may be called, becomes short 

 and thick, with the head drawn in. It spins an open-work 

 platform of silk on the under side of a leaf; its tail is firmly 

 anchored in the mass of silk by certain hooks at the end, 

 and meanwhile it throws around its body near the head a 

 strong silken cord as a support. Our Turnus chrysalis is 

 not bright-colored, but allied in color to a dry leaf or piece 

 of wood, so as to be easily overlooked by birds. Here it 

 remains through the winter until the end of the succeeding 

 May or first of June, when the butterfly within, which has 

 been growing rapidly during the preceding warm days, by 

 its convulsive struggles bursts the pupal skin on the back, 

 forcing the covering of the head and mouth-parts aside, and 

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