a. 



INSECTS. 103 



and the abdomen. In this way the junction of the 



pro-thorax and meso-thorax is lifted up, and the spine 



drawn as far as possible out of the furrow. As soon 



as the beetle has taken up this attitude, it can 



spring back into its usual position by lifting the two 



ends of the body and pressing the spine forcibly back 



into the furrow, 



whereby it is jerked g ^.a,^£r 



against the ground " 



with such a shock 



that its elasticity 



makpq it, <an-riTiD- in+.n ^'®- '5.— A Skipjack lying on its back and 



lUdKes a spring miO aoaWt. to spring up. a, head; 6, spine of tlie 



the air where it turns pro-thorax ; c, meso-thorax ; d, meta-thorax ; 



, ' - e, abdomen. 



round and comes 



down again ventral side below. The larvse ("wire- 

 worms," Fig. 74, 1) are like meal-worms, elongated, 

 always flattened on the ventral side, and sometimes 

 on the dorsal side as well. The head is dark brown, 

 the twelve remaining segments of the body yellow to 

 yellowish brown ; the first three segments of the body 

 bear three pairs of very small legs ; the last segment 

 has a pair of caudal pro-legs. 



Many species of click beetle are quite harmless, 

 since they only devour decaying vegetable matter, 

 either in humus or in the rotting substance of dying 

 trees. There are also species, however, the larvse of 

 which feed on the living roots of plants. The wire- 

 worms of Lacon ifnurinus, which are tolerably thick 

 and have a flattened tip to the abdomen, devour the 

 roots of fruit-trees, rose-bushes, various vegetables 

 (lettuce, cabbage, onions, turnips) and flowers; they 

 are principally to be found in garden soils rich in 

 humus. The relatively small hairless wireworms 

 which do great damage, especially to grain-plants, 

 but also to potatoes, carrots, turnips, rape, hops, and 

 almost all the plants of our arable land, belong to 

 Agriotes lineatus or A. obscurus; the larger and 

 more hairy wireworms destructive in cultivated land 



