OUTLINES OE ENTOMOLOGY. 81 



little mat or tuft of silk upon some convenient surface. Into this it 

 entangles the hooks of the hind legs, and loosening its hold in front 

 and curling up the head, it suffers itself to drop and hang by these anal 

 pro-legs. In this position it remains from twelve to thirty-six hours. 

 The skin then bursts open just back of the head, and the anterior end 

 of the chrysalis is protruded. By violent exertion, in alternate length- 

 enings and contractions, the larval skin is shoved backward until it 

 forms a shriveled mass near the point of attachment. The crowning 

 effort is now to be made in withdrawing the tail of the chrysalis and 

 fixing it into the little mat of silk prepared for it. The chrysalis, it 

 must be remembered, is not yet hard and stiff, but is capable of con- 

 siderable motion ; accordingly, by a sharp contraction, a portion of the 

 larval skin is firmly grasped between two of the abdominal joints, and 

 with only this slight hold the hinder end of the chrysalis is withdrawn 

 from the old skin, and, with a vigorous thrust, the little spike, termed 

 the cremaster, with which it is provided, is struck sharply into the tuft 

 of silk. Sometimes the first stroke suffices to fix it ; in other cases 

 two or three efforts are required, and, occasionally, there is utter fail- 

 ure and the chrysalis drops to the ground. When the chrysalis is made 

 fast it whirls itself rapidly round and round to detach the larval skin 

 and to more firmly entangle the barbs of the cremaster. After this 

 the chrysalis contracts and hardens, and the beautiful colors which 

 characterize the particular species are displayed. 



Among toe most beautiful and most easily recognized genera of 

 the four-footed butterflies may be mentioned Danais, Argynnis, Apa- 

 tura, Vanessa, Orapta and Hipparchia. The Archippus butterfly 

 (Danais archippus, Fabr.) is one of the most common and abundant 

 species. The wing expanse is between four and five inches, the color 

 a bright red-brown with black veins and black border in which are set 

 two rows of white dots. The larva feeds on the milkweed or silkweed 

 (Asc elepias},and is elegantly colored in transverse stripes of black,white 

 and yellow, with a pair of black velvety horns on the third and eleventh 

 joints. The chrysalis is shaped like a lady's ear-drop, and is of a clear 

 green color, ornamented with black and gold. 



The Argynnis butterflies have broad velvety wings of a tawny 

 orange color, shaded and spotted with dark-brown on the upper sur- 

 face, while the under sides are resplendent with numerous silvery spots. 

 In these species the antennae terminate in a large, roundish knob. The 

 larvae are covered with spines and feed upon violets. 



The Hackberry butterflies (genus Apatura) are of a dull brown, 

 mottled with white and black spots. The eggs of A. clyton (see Fig. 33) 



