NATURAL HISTORY STUDIES 



magnificent evolutions over the beech trees. All 

 this was performance without practice, for the 

 swallows had not been able even to extend their 

 wings in their narrow prison. 



In the familiar case of the spider's web, there is no 

 evidence that the spinner improves by practice. 

 The first web made by the young spider has all the 

 parts seen in the web made by the adult. As 

 garden spiders grow older the thread becomes 

 thicker and the web larger ; there are a few more 

 radial rays and a few more loops in the spiral, but 

 these differences are connected with ; the increased 

 weight of the spider and the increased size of the 

 spinning organs. There is more material to work 

 with, and the web is a little more substantial, but 

 there is no real change, nor need for any. 



We shall take two or three instances of instinct 

 from the works of the great entomologist, Henri 

 Fabre, whom Darwin called "that inimitable 

 observer." 



Picture the ringed Calicurgus wasp, which first 

 stings its captured spider near the mouth, thereby 

 paralysing the poison claws, and then, safe from 

 being bitten, drives in its poison needle with perfect 

 precision at the thinnest part of the spider's armour 

 between the fourth pair of legs. 



Looking in another direction, what can we say 

 of the mother of the Halictus bee family, who, 

 after prolonged maternal labours, becomes in her old 

 age the portress of the establishment, shutting the 

 door with her bald head when intrusive strangers 

 appear, opening it, by drawing aside, when any 



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