144 INSECT BEHAVIOR 



out before the foliage is entirely consumed. The bush is then ruined 

 until the following spring. 



Ten days after being deposited upon the food plant, the eggs split 

 open in the center. One unfamiliar with the cecropia's life history 

 would be very much surprised to see the tiny, black-spined cater- 

 pillars which emerge from them. At this age, they are jet black and 

 scarcely a quarter of an inch in length. The body is armed with 

 six rows of eleven and sometimes twelve stout spines, which, no 

 doubt, are terrifying enough to their natural enemies. When about 

 five days old, a tiny orange ring appears around the base of every 

 spine. This is a sign that the larva, as the caterpillar is scientific- 

 ally termed, is about to cast its skin. That is to say, it has grown 

 too large for its birthday suit and therefore must have a larger one. 



The cast is intensely interesting to watch, as the old dry skin may be 

 seen to split, at first near the head and finally down the back until 

 it reaches a point directly above the last pair of legs. At this juncture 

 the larva simply crawls out, bearing a new suit of the brightest 

 yellow, with steel blue spines, leaving the old black cast-off sticking 

 to whatever substance the larva had fastened it to. 



The cecropia caterpillar grows too large for its skin four times 

 during its life, shedding each time, and the colors changing some- 

 what with every cast. The last moult takes place when the larva is 

 twenty-six days old. The body color is then a beautiful deep foliage 

 green and the spines are varied in orange, yellow, and the brightest 

 imaginable blue. For eleven days after this cast the giant caterpillar 

 goes on feeding as before, finally reaching a length of nearly five 

 inches before starting to spin its cocoon. Indeed at this period of 

 its life, it is hard to imagine that this great green worm could be 

 connected in any possible manner with the tiny, black-spined larva 

 of thirty-seven days before. 



Although defenceless, the cecropia's protection is complete. Its 



