COLEOPTEEA. 503 



him board and lodging. The Ptilodactydce, the Eucineti, and the 

 Cebrios belong to the same family. The first two are exotics. 



The Elateridce are rather large insects, often of hard texture, 

 having the prosternum prolonged into a point (Figs. 549 and 

 550), and the antennae indented saw- wise. They have the power 

 of jumping when placed on their backs, and of alighting again 

 on their legs. Hence their name of Elater (derived from the same 

 root as the word elastic). They produce, in leaping, one sharp 

 rap, and often knock many raps when they are prevented from 

 projecting themselves. This is the mechanism which permits the 



Fig. 550. Jumping organ of the Elater, 

 seen bide ways. 



Fig. ,549. Jumping organ Fig. 551. Larva of ihe Elater. 



of the Elater. 



skip-jack to execute these movements. It bends itself upwards 

 by resting on the ground by its head and the extremity of 

 the abdomen ; and then it unbends itself suddenly, like a 

 spring. The point at the end of the thorax penetrates into 

 a hollow of the next ring; the back then strikes with force 

 against the plane on which it rests, and the animal is projected 

 into the air c It repeats this manoeuvre till it finds itself on 

 its belly, for its legs are too short to allow of its turning over. 

 Its structure supplies it with the means and the strength of 

 rebounding as many times as it falls on its back, and it can thus 

 raise itself more than twelve times the length of its body. 



The larvae of the Elaters (Fig. 551) are cylindrical, with scaly 

 skin and very short legs. They live in rotten wood or in the 

 roots of plants. According to M. Goureau, they pass five years 

 in this state. 



The larvae of the genus Agriotes occasion considerable damage 



