INSECTS 



The facts of reproduction in animals are not well ex- 

 pressed by our name for them. Instead of "reproduc- 

 tion," it would be truer to say "repeated production," for 

 individuals do not literally reproduce themselves. Genera- 

 tions are serially related, not each to the preceding; they 

 follow one another as do the buds along the twig of a tree, 



Fk;. 63. The external structure of an insect 

 The body of a grasshopper dissected showing the head (//), the thorax (TA), 

 and the abdomen {Ab). The head carries the eyes (E), the antennae {Ant), and 

 the mouth parts, which include the labrum (Lm), the mandibles {Md), the 

 maxiilae IMx), and the labium {Lb). The thorax consists of three segments 

 (/, .?, j), the first separate and carrying the first legs (£1), the other two com- 

 bined and carrying the wings (W"2, #'.t), and the second and third legs (/.2, Zj). 

 The abdomen consists of a series of segments; that of the grasshopper has a 

 large tympanal organ {Tm) y probably an ear, on each side of its base. The end 

 of the abdomen carries the external organs of reproduction and egg-laying 



and buds on the same twig are identical or nearly so, not 

 because one produces the next, but because all are the 

 result of the same generative forces in the twig. If the 

 spaces of the twig between the buds were shortened until 



[102) 



