THE SWALLOWTAH^S 69 



it proceeds to make a more enduring structure. In this 

 case it does not need to bite a channel along one side of the 

 midrib as it did before, but instead it begins to spin silken 

 threads transversely across the upper surface in such a way 

 as to fold over the border of the leaf and make a tubular 

 chamber in which it has plenty of room to move about. 

 It uses this as its home for some time thereafter, wander- 

 ing out at evening to feed upon neighboring leaves as its 

 hunger necessitates. In this way it continues to feed and 

 grow for a week or two. Then it finds it necessary to 

 construct still another home, which it does by bringing 

 together the opposite sides of a leaf, taking care to have a 

 door-like opening at the base of the blade next the leaf 

 stalk. This third home serves it to the end of its larval 

 existence. It goes in and out as necessary, remaining con- 

 cealed when it casts its skin and until the body tissues 

 harden afterward. Apparently it devours the cast skin 

 and thrusts the hard covering of the head out of the nest. 

 Consequently these little homes are clean and sanitary and 

 serve admirably their protecting purpose. 



The full-grown caterpillars have the curious appearance 

 of those of the other Swallowtails. The third ring behind 

 the head is greatly swollen, making, with the rings di- 

 rectly in front of it, a characteristic picture suggesting a 

 grotesque face with large eye-like spots at the top. The 

 general color is green, darker above than below, and there 

 are six rows of blue dots along the body. {See plate, page 80.) 



When ready to change to the chrysalis, the caterpillars 

 desert their leafy homes and on a twig or board or stone 

 each spins a bit of silken webbing and a silken loop. They 

 now change to chrysalids which are likely to resemble the 

 color of the background and which are somewhat smoother 



