Their food was the meat they killed in the chase, or seeds and roots, grubs or reptiles.
Stridulating organs among beetle-larvae have been noted, especially in the wood-feeding grub of the stag-beetles (Lucanidae) and their allies the Passalidae, and in the dung-eating grubs of the dor-beetles (Geotrupes), which belong to the chafer family (Scarabaeidae).
The heavy grubs of Geotrupes, their c b FIG.
The larvae of Elateridae are elongate, worm-like grubs, with narrow bodies, very firm cuticle, short legs, and a distinct anal proleg.
The larvae are white, fleshy, apodal grubs, with a series of tubercles along each side of the body; the head is round, and bears strong jaws, and sometimes rudimentary ocelli.