CONTROLLED PUPATION 447 



the same result from my experiment. Those within the tubes 

 have transformed to pupae, but those imprisoned in the ver- 

 million-nut still writhe in the larval form. I keep the prison- 

 ers in their cell from April 20 until the twelfth of May. 

 Still there is no change from the larval form, yet any day 

 I may remove one to a tube of earth and forty-eight hours 

 later recover it as a pupa! It is a strange condition indeed, 

 but I think I see its significance. 



When I open the fruit on the tenth of May, I note that 

 the true nut within has sprouted ever so slightly. Each day 

 the cotyledons of the new tree are swelling within the shell 

 that holds them, pushing upwards in response to the light 

 which beckons. Were the nut lying naturally upon the moist 

 floor of the forest, the young tree's progress would be even 

 faster. As length the pressure becomes too great for the 

 nut's outer shell to bear. It yields to the vortex of a new life, 

 splits open and at the same time the imprisoned larvae find 

 the long-waited-for exit to the friendly mould of the forest. 



Here is a condition among insects previously unknown 

 to me. It is a remarkable adaption to the condition of the 

 creature's strange habitat, that has brought about a deviation 

 from the rule. In short, the young flies may hasten or post- 

 pone pupation at will! I would have hesitated to set forth 

 such a statement, even as a remote possibility, were it not 

 for my experiments that cannot be denied. One learns to 

 expect the unexpected in nature, but who would go so far 

 as to accuse her of running even so tiny a creature as this 

 nascent fly, without a schedule? She is forced to surrender 

 here to conditions self-imposed. If her children within the 

 vermillion-nut lie imprisoned without food for a fortnight 

 or more, it matters not. When release comes they are none 

 the worse for their experience. If they are spilled roughly 

 on the ground from a freshly broken nut a month before 

 their brothers, so much the better. They have no set time for 

 pupation. They will become flies just the same! Thus 

 Nature has endowed them with ability to meet successfully, 



