244 LIFE STORIES OF AUSTRALIAN INSECTS. 



but the back legs have only 4 joints. (Plate 

 30. Fig. 4). The joints are usually shorter 

 than those of carabs and so are more closely 

 packed. 



(3) The legs are not particularly fitted for 

 running. These beetles are chiefly scaven- 

 gers feeding on decaying vegetable and 

 animal matter. 



(4) The mouth parts are suitable for chewing; 

 the mandibles are not specially formed to 

 seize prey. 



There is one tenebrionid pest ; it is the "flour 

 grub," The mother insect lays her eggs in flour, 

 etc., and the grub feeds on it and spins a loose 

 silken cocoon in the flour, bran, pollard, or chafif. 

 These beetles, Tenchrio molitor, are common in 

 stables, mills, and fowls' food. . The larvae may 

 pupate in corners of the boxes in which the foods 

 are kept. 



Life History of Tenebrionids. — The eggs are laid 

 under logs, in cracks in the soil, in crevices in logs, 

 and in bark near the ground. The larva hatches out. 

 It is an elongate narrow grub with thick integu- 

 ment. The legs and jaws are not so strong as are 

 those of the carab larva. There is usually only one 

 process at the end of the body. This probably aids 

 in locomotion. It feeds on vegetable matter chiefly, 

 and is a scavenger. 



It pupates under logs or similar places. The 

 adults are also scavengers, usually feeding at night. 

 A few are carnivorous. 



We have noticed three groups of tenebrionids: 



