1 30 Life and Immortality. 



So securely does the caterpillar hold on to its house, that 

 one would suppose that its body was lashed to the inside. But 

 no, its body is unhampered, for it can turn itself easily around 

 in its case, and go out at either end, although the head is 

 generally directed upward. It clings to the inside with the 

 hooks upon its hinder feet, and so tenaciously, too, that the 

 writer has never been able to pull one out, being checked by 

 the fear of tearing the creature in two. And now to the 

 mode of attaching the leaf-cuttings to the case. This is 

 always done at or near the mouth of the sac. The Ephemera- 

 form larva is a growing creature, unlike the moth itself, which 

 emerges a perfect insect of full growth. It commences life as 

 a small worm, eats small quantities, and, as may be observed, 

 down towards the foot of the case sews on very small tags. 

 But after it has fastened on these pieces to the mouth, it 

 grows itself, and so also does the case, which it continually 

 stretches and enlarges. Hence the mouth of the case is 

 continually changing, moving upward as the worm feeds, so 

 that the pieces sewed upon the cap of the case thus appear, 

 in an adult caterpillar, precisely as they are seen scattered 

 along the outside from top to bottom. And now, as to how 

 the pieces are put into the case, I shall endeavor to explain. 

 That the worm cuts purposely through the twig which it 

 needs for the case, I feel certain. Of course the outer or 

 detached part drops down. But, while eating, the worm 

 frequently, quite constantly, indeed, spreads its viscid silk 

 along the leaf and so keeps it attached on both sides to the 

 upper rim of the sac, or to its own mouth-parts, and thus the 

 tip of the twig or leaf, instead of falling to the ground when 

 it is severed from the stem, simply drops alongside of the 

 case, to which it is held by the slight filament that attaches 

 it to the sac, or, as happens in many instances, remains 

 attached to the caterpillar's spinneret. In either case the 

 leaf, twig or stem remains, and, after being drawn up, adjusted 

 and tightened by the worm, adheres tightly. As the creat- 

 ure is forever moving its spinning-tubes around the top of 



