ARTHROPODA. 



243 



the spring-tails and snow-fleas (Fig. 89). Probably 

 these have never had wings. There are some other 

 wingless types which are related to forms that have 

 wings. Such are some of the workers among the ants, 

 many plant lice, certain scale insects, walking-stick, 

 fleas, and other parasitic forms. It is believed that 

 these have lost their wings through gradual adjustment 

 to their special methods of life. 



FIG. 90. Katydid (Cyrtophyllus perspicillatus) , natural size. Photo by Folsom. 



Questions on the Figure. How many pairs of appendages are 

 vi-ible in the figure? How many are really present? To what order 

 of insects does the katydid belong? What are its feeding habits? 

 What can you find of its development? Does it have a meta- 

 morphosis? 



260. The Orthoptera (Grasshoppers, Crickets, Katydid, 

 and Cockroaches). These may be taken as illustrative 

 of the less complex and less highly developed insects. 

 They commonly have four wings, the anterior pair being 

 somewhat hardened and the posterior folding up length- 

 wise beneath these when at rest. Their mouth parts are 

 adapted to biting and they are voracious eaters. The 

 crickets, katydids, and cockroaches (Fig. 90) are nocturnal 



