216 BOMBAY DUCKS 
of time that the eggs require to hatch varies with 
different species, and is often considerably longer than 
the time occupied by the Rhyuchium egg. 
The larva soon passes into the pupal state. It does 
not spin a cocoon as the silkworm moth does. The 
transformation into the zmago or adult occupies less 
than three weeks. As there is no cocoon, one might, 
if the creature could live in the light, watch the won- 
derful metamorphosis actually taking place, but light 
appears to kill the pupa. About seventeen days after 
the egg had been laid I dug out another pupa. It had 
assumed the adult wasp-like form, was almost white in 
colour, and looked what it was—an unfinished wasp. 
Over the last cell I tied a piece of muslin to make 
a cage into which the imago would have to fly on 
leaving the nest, but I might have spared myself the 
trouble. Twenty-five days after the closing of the cell, 
I noticed that a hole had been gnawed in the muslin, 
and, looking into the nest, I saw a hole through the 
roof of the cell and knew that the wasp had flown. She 
had been able to adapt herself to circumstances. She 
had used her jaws, with which instinct had taught her 
to rasp away the roof of her cell, to cut a hole in the 
muslin, and thus gained her liberty. 
