LETTERS ON ENTOMOLOGY. 27 
cockroaches abound and are a great nuisance, 
the white ants are very useful in clearing them 
away. The Mantes, which are the most terrible 
and ferocious of insects (though from their ap- 
pearing to sit almost upright they are called 
praying-flies), have their fore-legs constructed 
like a sabre, and they dexterously use them as 
such to cleave their enemy in two, or cut off its 
head, often treating each other in this way. I 
believe these alarming little soldiers are not found 
in England. The scorpion is equally ferocious. 
Maupertuis put a hundred scorpions together, 
and a general and murderous battle immediately 
began. In a few days almost all were devoured 
by the survivors. They frequently eat their 
young as soon as born. Spiders are almost as 
fierce in their habits, destroying each other in 
great numbers. 
Many animals feed upon insects; the hedge- 
hog and mole are insectivorous, the latter being 
said to devour great quantities of the wire- 
worms. The swine are extremely fond of the 
grubs of the cockchafers, and if the grass is 
damaged by them, the rooting of it up will per- 
haps do more good than harm. The Ratel eats 
bees, and the Armadillo, locusts ; but the great 
Ant-eater is most deserving of notice, for he 
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