INSECTS: THEIR EARS AND EYES 191 



head, but on the first essay toward 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 sen- 

 sorium, 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 

 Skipjack (Elater)] but many members of the same family 

 show the same structure in a far higher degree, the angle 

 being drawn out in a long slender rod, which (with its 

 fellows) imparts to the antenna the appearance of a comb. 



But much more curious and beautiful are the antennae 

 of many Moths, which often resemble feathers, particularly 

 in the group Bombycina, of which the Silkworm is an ex- 

 ample; and in the male sex, which displays this structure 

 more than the female. But I will show you a native 

 example. 



This is the antenna of a large and handsome, and not at 

 all uncommon moth the Oak Egger (Lasiocampa quercds). 

 It consists of about seventy joints, so nearly alike in 

 size and outline that the whole forms an almost straight 

 rod, slightly tapering to the tip. Each joint, however, 

 sends forth two long straight branches, so disposed that 

 the pair make a very acute angle, and the whole double 

 series of seventy on each side form a deep narrow groove. 

 These two series of branches, being perfectly regular and 

 symmetrical, impart to the antennae the aspect of exquisite 

 feathers. 



It is, however, when we examine the elements of this 

 structure in detail, using moderately high powers of en- 

 largement, that we are struck with the elaborateness of the 



