156 INSECTS ABROAD. 



examine, and held on their backs, the mode of jumping is at 

 once seen. A very strong spine extends from the " pro-sternum," 

 or first portion of the thorax, and projects so far backwards that 

 its end passes into a deeply-grooved cavity formed by a projection 

 between the middle pairs of legs. A side view of this spine 

 shows that it is shaped just like the "pall" and ratchet in 

 machinery; indeed, so exact is the resemblance, that in looking 

 at the leaping spine of a large Elater, it seems as if the pall and 

 ratchet must have been copied from it. 



Now for its use. When the Beetle falls on its back, it first 

 feels about with its legs, trying to find a foothold, and, after 

 failing, makes up its mind to leap. It gathers up its legs closely 

 to its body, and, in some instances, lays its antennoe in two 

 grooves which run along the under surface of the thorax. It 

 then bends its thorax very far back, so as to arch itself com- 

 pletely from the surface on which it is lying. This movement 

 lifts the end of the spine just out of the notch in which it has 

 lain, and which is so made that whereas the spine can be slipped 

 out easily enough, it cannot be restored to its place without some 

 force and a sharp jerk. 



The insect then begins to straighten its body, but is prevented 

 by the end of the spine. Were the spine perfectly stiff, the 

 insect would probably never straighten itself again; but being 

 highly elastic, it bends, and then springs into its place with a 

 sharp clicking sound, thereby jerking the shoulders — if we may 

 so call them — against the ground, and flinging the insect high 

 into the air. Some writers have said that the end of the abdomen 

 and the head are struck against the ground, but I am certain 

 that the method which I have described is that which is em- 

 ployed by the Skipjack Beetles. 



The name Elaten*, signifying "striking" or "bounding," refers 

 to this remarkable power of leaping. 



Our example of the Elaterides is the curious Beetle called 

 Alaus mcerens, a native of India. The whole upper surface of 

 this insect is cream colour clouded with grey, and covered with 

 a number of black spots, streaks, and patches, too numerous to 

 describe, and varying in different specimens. There is, however,, 

 always a large patch on the outer edge of each elytron, nearly in 

 the middle. On a closer inspection it is evident that the real 



