XVII 



INSECTA: COLEOPTERA 



257 



(Fig. 189, A) so that only the front of the thorax and end 

 of the ahdomen and 

 elytra touch the ground, C 



and the spine just rests 

 on a ridge above the 

 groove ; then it suddenly 

 contracts the muscles, so 

 that the spine is forced 

 past this ridge into the 

 groove, with a click ; this 

 sudden movement causes 

 the arching of the body 

 in the reverse direction, 

 and the tips of the elytra 

 strike the ground virith 

 such force that the recoil 

 jerks the body two or 

 three inches into the air 

 usually reversing its posi- 

 tion at the same time, so 

 that the beetle alights on ' 

 its feet (Fig. 189, C^. 



The larvae of these 

 beetles are the trouble- 

 some " wire - worms " 

 which live in the ground, 

 and some species of which 

 do great damage to the 

 roots of plants. They 

 are small, yellow, rather 

 stiff creatures, with an 

 elongated thin body of the same thickness throughout its 



TtAt. siz«. 



Pig. 189.— Skipjack Beetles. 



A^ Beetle on its back preparing to jump. 5, 

 Jumping and at the same time reversing 

 its position as a result of its action in posi- 

 tion A. G, Beetle once more on the ground 

 after having been in positions A and B suc- 

 cessively. 





FiQ. 190. — The "Wire-worm or Larva of the Click Beetle. { x 3.) 



length, and with six short insignificant legs and a process 

 VOL. I s 



