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CHAPTER XII. 



POLYMORPHA {contluiwd)— Family ELATERIDAE. 



{Click Beetles.) 



Although species of this family are often to be met with in the forests 

 throughout India, but Httle is at present known as to their habits. Elaterid 

 larvae are commonly found in the decaying bast and sapwood of dying 

 or dead trees, but few instances are on record of the beetles having 

 been bred from the grubs. On a few occasions I have obtained beetles in 

 this way, as e.g. Ludigenits and Pedocera which infest the semul (Bombax 

 malaharicum) in Assam, Alans in sal wood from Balaghat in the Central 

 Provinces, and two other species, Lacon and Melanotus, in spruce in the 

 Himalaya. In all these cases the larvae obtained have answered to the 

 well-known circular, hard, shining brown type of elaterid grubs. 



The elater beetle is easily recognized, the head being sunk in the large 



prothorax, the latter being squarish in outline, with the 

 Characters. posterior angles prolonged into points behind. On the 



under-surface this prothorax has a pointed process 

 medianly which fits into a cavity or socket on the mesosternum. This 

 arrangement is directly adapted for a special purpose, the insect, which 

 is flat and rather broad in build, when on its back being unable to turn 

 over again. It accomplishes this operation by pressing upwards the pointed 

 process, and thus freeing it sharply from the socket ; momentum is thereby 

 obtained, and the insect is shot up in the air, coming down on its ventral 

 surface again. It is owing to this habit, present in some species, that the 

 insect obtains the name of skip-jack or click beetle, a sharp " click " making 

 itself heard when the process is released from the socket. The antennae are 

 often short and serrate, the serration being at times much prolonged. The 

 elytra are very hard, and cover the abdomen. The beetles vary in size from 

 about an inch or more downwards, the larger being often brightly coloured, 

 as in Alans pntridus shown in fig. 148. The smaller ones are usually dull- 

 coloured ; yellows, browns, and blacks predominating. 



The grubs of the forest species known are elongate-cylindrical (figs. 



30, d, and 150), and shining brown or yellow in colour. 

 Larva. usually darker above than below, with three pairs of 



thoracic legs and one or more processes on the last 

 segment. The chitinous covering of the whole grub is extremely hard and 

 horny in consistency, there being but little clear definition of the abdominal 

 segments, which are more or less equal in size. I have taken grubs from 

 two inches in length downwards. 



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