THE PUTA OR CHRYSALIS. 103 



to • the wall or branch in a corresponding position 

 on the opposite side of its body. In this way a 

 loop is formed which will effectually prevent the 

 Caterpillar from falling as he sinks into a dormant 

 state. But it is not yet strong enough, the thread 

 being of excessive fineness, and therefore the process 

 is repeated about fifty times, as observed by Reau- 

 mur, when the number of threads is generally deemed 

 sufficient. In order to secure a sufficient degree 

 of slackness in the loop, to allow for the thickening 

 of the body in the chrysalis state, Reaumur de- 

 scribes, at considerable length, a process by means 

 of which that necessity is ingeniously secured ; but 

 I have, nevertheless, observed that the loop round 

 the chrysalis often appears uncomfortably tight, 

 nearly cutting a dent into the external skin, as re- 

 presented in Plate III. 



A different method is pursued by the Caterpillar 

 of the Great Swallow-tail Butterfly, the handsomest 

 of our native species, in consequence of the com- 

 parative want of flexibility in its more robust body. 

 Not being able to turn the head freely backward to 

 form a loop across the middle of its body, it makes 

 the loop immediately in front of its head, into which, 

 when complete, it gradually forces its body, seg- 

 ment by segment, till it has attained the position in 



