CONTROLLED PUPATION 79 



insect. I can but surmise. Later the eggs give place to tiny wiggling 

 larvae, whose movements depend upon contractions of their muscles, 

 for they are devoid of feet. They feast like gluttons upon the nascent 

 flesh of the ripening fruit until it comes time to pupate. 



From what we know of many other flies, we have seen that it is 

 natural for them to pupate within the ground, or at least in a position 

 from which they may work their way to the light of day when nature 

 has transformed them into perfect insects. The larval flesh fly bur- 

 rows below her carrion to transform in the damp soil beneath, the 

 house fly in its bed of manure finds escape an easy matter, the mosquito 

 transforms in the water, but what of our flies born within a tough- 

 shelled nut in the highest forest branches? How are they to release 

 themselves from such a prison after the feast is over? As we have 

 seen, they reach the ground by falling, when the nut is plucked by 

 some roaming monkey, or as it falls anyway when ripe, carrying its 

 living burden earthward. But that is not answering the question. The 

 larvae must burrow into the forest soil to transform and issue suc- 

 cessfully as a perfect insect. How, then, is this feast accomplished? 



The nut which I cut open contained eleven larvae. They appeared 

 to be full grown and ready to pupate, at any rate, there was no more 

 pulp left for them, and if they were hungry they must eat again 

 that which had been digested once. No, they simply wiggled about 

 frantically as though searching for an opening and swarmed to the 

 hole I had cut. 



I remove two of them to tubes of soil slightly dampened. The 

 remainder are locked once more in their prison. In the tubes con- 

 ditions are, as nearly as I can make them, like those of the forest floor. 

 The larvae move here and there from fright in their new environ- 

 ment for a minute or two, but presently one thrusts its pointed head 

 into the soil and commences to burrow. Soon it is followed by the 



