278 INDIRECT BENEFITS DERIVED FROM INSECTS. 



in charge to keep the animals of their own class within 

 their proper limits ; and I cannot doubt that you will re- 

 cognise the goodness of the Great Parent in providing 

 such an army of counterchecks to the natural tendency 

 of almost all insects to incalculable increase. But before 

 I quit this subject I must call your attention to what may 

 be denominated cannibal insects, since in spite of those 

 declaimers who would persuade us that man is the only 

 animal that preys upon his own species a , a large number 

 of insects are guilty of the same offence. Reaumur tells 

 us, that having put into a glass vessel twenty caterpillars 

 of the same species, which he was careful to supply with 

 their appropriate food, they nevertheless devoured each 

 other until one only survived 15 ; and De Geer relates se- 

 veral similar instances . The younger larvae of Calosoma 

 Sycoplianta often take advantage of the helpless inacti- 

 vity into which the gluttony of their maturer comrades has 

 thrown them, and from mere wantonness it should seem, 

 when in no need of other food, pierce and devour them. A 

 ferocity not less savage exists amongst the Mantes. These 

 insects have their fore legs of a construction not unlike 

 that of a sabre ; and they can as dexterously cleave their 

 antagonist in two, or cut off his head at a stroke, as the 

 most expert hussar. In this way they often treat each other, 

 even the sexes fighting with the most savage animosity. 

 Rosel endeavoured to rear several specimens of M. reli- 

 giosa, but always failed, the stronger constantly devour- 



3 " Even Tiger fell and sullen Bear 



Their likeness and their lineage spare. 



Man only mars kind nature's plan, 



And turns the fierce pursuit on Man ! " 



Scott's Rokeby, canto iii. 1. 

 h Reaumur, ii. 413. c De Geer, i. 533. iii. 361. v. 400. vi. 91. 



