ZOOGENESIS 



tail waving, and the tail acts as a drag lessening the 

 shock of landing. 



I have remarked that in their last stage w^hen they 

 are fully grown and sexually mature most insects are 

 capable of flight. In this stage most of them eat but 

 little, and many of them do not eat at all. Most 

 insects eat enough, or nearly enough, in their early or 

 larval stages to last them all their lives. 



For young insects rapid or extensive locomotion in 

 most cases is not necessary. Their preoccupation is 

 to keep as close as possible to their food supply, which 

 usually is localized. Young insects, especially in the 

 later stages, gorge themselves so that when adult they 

 can fast. It is in the adult stage that, in most insects, 

 all the traveling is done; the adults wander far and 

 wide searching for new supplies of food for the 

 coming generation. Through their capacity for long 

 continued flight, which is greatly increased by the 

 absence of the necessity for feeding, the insects 

 largely overcome the handicap to their powers for 

 distribution imposed by their small size. 



Most spiders are distributed by a different method. 

 All of the spiders are predacious, feeding on creatures 

 weaker than themselves, mostly on insects. Natu- 

 rally in catching prey strong spiders have the advan- 

 tage over weaker ones, and large ones over smaller 

 ones. Therefore the logic of the case would seem to 

 be that spiders should fly in their early weaker stages 

 and not as fully grown and powerful adults, and this 

 is what actually happens. 



Spiders are wingless, but their lack of wings is 



