INSECTS IN RELATION TO PLANTS. 530 



the larva of Zabrus belongs to these, for in the spring of the year 1812, 

 in the vicinity of Halle, whole corn-fields were devoured by their vora- 

 city *. During the day it buries itself six inches deep in the earth, 

 and towards evening it comes to the surface, and then eats into the pith 

 of the roots, biting off the blade closely above the ground. Thus in the 

 above year twelve hides of wheat, rye, and barley were destroyed. As 

 the genus Amara, which is closely allied to Zabrus, has in its perfect 

 state a very similar mode of life, particularly the division of it known 

 by the name of Leirus, we may conclude that their larvae also live 

 upon the roots of grass. We may perhaps also class here the larva 

 first described by Walfrod, and which he considered as a wire worm 

 (the larva of Elater segelis, Gyll.). Kirby and Spence t consider it 

 as the larva of a Staphylinus, but this is contradicted by the difference of 

 the mode of life of the other individuals of this tribe. It lives, namely, 

 at the roots of wheat, devours the just germinating grain, and in older 

 plants it consumes the root only. According to Sir J. Banks the same 

 larva destroys turnips, and sometimes from forty to fifty individuals 

 are found in one root. 



In addition to these it is especially the larvae of many of the Elaters 

 which attack the roots of corn and other plants. We know that the 

 wire worm, which is the larva of Elater segetis, Gyll., (E. lineatus, 

 Lin., E. striatus, F.), feeds upon the roots of corn, as well as that the 

 larva of the allied Elater obscurus, Lin., (E. variabilis, Fab.) feeds 

 upon the roots of almost all kinds of garden plants and culinary vege- 

 tables, and sometimes, in places where they have much increased, pro- 

 duce great injury. 



The majority of the larvae of those Lamellicornes which in their per- 

 fect state feed upon leaves, as the Melolonthee and Cetonice, devour, in 

 that state, the roots of plants ; these thick, fat, yellowish white larvae are 

 well enough known to farmers, and frequently produce great injury to 

 corn. Multitudes of the larvae of Melolontha rujicornls actively par- 

 ticipated in the devastation committed by the larvae of Zabrus gibbus 

 in the vicinity of Halle. The more numerous and more generally dis- 

 tributed larvae of Melolontha vulgaris, the common cockchafer, are not 

 less injurious, particularly as they pass several years as larvae, and every 

 year new ones are produced. An instance occurred near Norwich, in 



* Germar's Mag. vol. i. parli. p. l,&c. 

 t Introduct. to Entotn. iv. Letter xlv. 



