210 



HIGH SCHOOL ZOOLOGY. 



placed, and to which, the carnivorous locusts and crickets ai'e 

 neai'ly allied ; but the wings may be entirely absent, as in the 

 singular walking-stick insects {Diapheromera femorata), or only 

 partly developed, as in some of the cockroaches and earwigs. 



The family Phasmidm contains some of the most striking cases of 

 protective resemblance to the environment, for the members may 

 resemble dried t>vigs, or even leaves of the trees on which they hve, as 

 in the case of the East Indian winged PkyUium. 



27. From the earwigs we are led to a group of insects char- 

 acterized by the entire absence of wings, and the pi-esence of 

 caudal appendages, equivalent to the cerci of the locust and 

 cocki'oach, and to the forceps of the earwigs. These are the 

 S})ring-tails (Thysanura), inconspicuous on account of their size 

 (Fig. 142), but interesting to the zoologist as the most lowly 

 organized insects, some of them (Fig. 143) even having rudi- 

 mentary legs on the abdomen, and thus resembling certain 

 Myriapods (Fig. 144). 



Pig. 142.— Podura. 



Fig. 143-Cam- 

 podea. 



Fi?. 144— Soolo- 

 pendrella. 



28. The characters of this class, the Myriapoda, may be 

 therefore briefly examined before proceeding to the higher In- 

 secta. It is a small gi'oup of less than a thousand species, in 

 which the numerous segments of the body may each bear one 

 or two pairs of ajipendages, but are never gi'ouped, as they are 



