162 EVENINGS AT THE MICROSCOPE. 



cakes ; and being connected only at one end of the long 

 axis, they open and shut at the pleasure of the animal, like 

 a long pocket memorandum-book of three leaves. 



But this structure is seen to still greater advantage in 

 the much larger Cockchafer, so abundant in May in some 

 seasons. For here the joints composing the club are 

 much more numerous (seven in the male, six in the 

 female), and they are proportionally longer and thinner, 

 and therefore more leaf-like. The insect widely expands 

 them, evidently to receive impressions from the atmo- 



AKTENNA OF COCKCHAFER. 



sphere ; when alarmed, they are closed and withdrawn 

 beneath the shield of the head, but on the first essay 

 towards escape, or any kind of forward movement, the 

 leaves are widely opened, and then, after an instant's 

 pause to test the perceptions on the sensorium, away it 

 travels. 



In some Beetles each joint of the series has one of its 

 outer angles more developed than the other, and so pro- 

 duced as to make, with the rest of the joints, a saw-like 

 edge ; you may see an example in this Click-beetle or 



