WONDERS OF INSTINCT 



the top is like the mouth of a Greek vase, gracefully 

 curved, worthy of a potter's wheel. After the 

 mother wasp has placed an egg in her well-fashioned 

 nest, she adds five to ten small caterpillars, which 

 she stings, and the next step is to close the orifice 

 with a cement plug, in which there is always set a 

 single tiny pebble. But the touch of perfection is to 

 be found inside, not outside. It appears that the 

 stung caterpillars that form the living larder inside 

 the wasp's cell have still a good deal of vigour, 

 and toss about when touched. Now the least pres- 

 sure would crush the delicate egg. So it is hung 

 by a thread from the roof of the cupola, and after 

 the wasp grub hatches, it makes the shell of 

 the egg into a flexible staircase so that it can reach 

 the caterpillars and bite them, yet retreat if they 

 are too fierce ! 



A second wonder is the way in which different 

 operations are linked together in a chain. The 

 grub of the Capricorn beetle burrows for three years 

 on end in the depths of an oak tree. But when it 

 is full-grown and the time of its change into a beetle 

 draws near, it moves to the margin and makes a 

 passage almost out, leaving only a film-like screen, 

 just as if it knew that the winged beetle to come 

 out of the pupa-case would otherwise be buried 

 alive. It then draws back a little in its gallery 

 and makes an outer barricade of particles of chopped 

 wood, and inside that again a partition like a white 

 skull-cap or acorn-cup, composed, strange to say, 

 of carbonate of lime and some organic cement. 

 The next step is to make to the inside of the partition 



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