328 



PTILOTA. 



In the Hemipterous insects we find a very numerous tribe, 

 composing the Lirnifean genus Cimex (bugs), able effectually 

 to defend themselves by the emission of a powerful scent, 

 which, although occasionally in a few species not disagreeable, 

 is in general very disgusting. 



In the Homoptera many species, as the frog-hoppers 

 ( CercopidcB), are enabled to leap very great distances, thus 

 avoithng their enemies; whilst some in their larva state 

 conceal themselves beneath a curious coating of froth. 



a, The Cuekoo-spit Insect {Aphrophora tpumaria). h. The mass of froth, c, Tlie pupa. 



The Diptera do not present any very striking instances of 

 insect defence; the rapidity of their motions, as well as 

 those of the insects composing the order Aphaniptera (fleas), 

 ought not, however, to be omitted. 



From this review of the means of defence in the various 

 orders of insects, it will be seen that distinct organs for 

 active defence are not possessed by the majority of these 

 creatures, but that they are amply compensated by equally 

 effective modes of counteracting the attacks of their foes, 

 consisting either in powers of evasion, as rapidity of flight, 

 strength in swimming, power in leaping, and velocity in run- 

 ning; or in powers of repulsion, as emission of powerful 

 odours, hideousness of appearance ; or powers of simulation, 

 whereby the appearance of death, or of some other objects, 

 is assumed. Thus we perceive that here, as indeed through- 

 out nature, the desire to prolong existence, and to per- 

 petuate the species, are the greatest ends of action. The 



