XVII 



INSECTA: COLEOPTERA 



249 



large black mark covers the hinder part of each of the 

 elytra. The under side of the thorax and also of the hind 

 end of the abdomen is black. 

 The body is strongly convex both 

 above and below, and consequently 

 movement is difficult on the ground, 

 though in the water the beetle is 

 very active. 



The larva is aquatic and has a 

 rather unusual appearance (Fig. 

 178). Its golden-brown body con- 

 sists of a head and eleven seg- 

 ments, prettily marked above with FlG 177 ._ The Sc reech Beetle 

 dark brown. The last segment (PdoUus Hermanni). 

 bears three long tail whisks, which 

 are used to some extent in swimming, and which do not 



FIG. 178. Larva of Peldbius Hermanni. 

 a, Line indicating real length. 



seem to be respiratory, for there are special little delicate 

 respiratory filaments under the thorax and first 

 three segments of the abdomen. 

 Cicindela, The l arvae an( l perfect insects of 

 the Tiger all the beetles so far mentioned have 

 Beetle, been aquatic and carnivorous ; allied 

 to them are the carnivorous Tiger Beetles, 

 which live on land. A common species on dry 

 loose soil is Cicindela campestris, a terrestrial 

 beetle that destroys a great many grubs harmful 

 to plants (Fig. 179). The soft larva lies in wait 

 for its prey in little vertical tunnels that it ex- 

 cavates in the ground, but the full-grown beetle is an active 



FIG. 179. The 

 Tiger Beetle. 



(Natural size.) 



