196 INDIRECT BENEFITS DERIVED FROM INSECTS. 



attack them in their entrenchments. Near sunset the ratel will sit and 

 hold one of his paws before his eyes, in order to get a distinct view of the 

 object of his pursuit; and when, in consequence of his peering about in 

 this manner, he sees any bees flying, he knows that at this time of the 

 day they are making for their habitations, whither he follows them, and so 

 attains his end.^ Another species of Viverra (^V. yrehensUis) is also 

 reputed to be an eager insect hunter. The young armadillos feed on a 

 species of locust ; but no quadruped can with more propriety be called 

 insectivorous than the ant-eaters (^Mi/rmecophaga) , which, as their name 

 imports, live upon ants. The great ant-eater, when he comes to an ant- 

 hill, scratches it up with his long claws, and then unfolds his slender worm- 

 like tongue (which is more than two feet long, and wet with saliva), and 

 when covered with ants draws it back into his mouth and swallows 

 thousands of them alive, renewing the operation till no more are to be 

 found. He also climbs trees in search of wood-lice and wild-honey. 

 Bats, as every one knows, are always flitting about in summer evenings, 

 hawking for insects : and the Lemur and monkeys will also eat them. 



Insects likewise afford a favorite kind of food to many reptiles: the 

 tortoise ; frogs and toads ; and lizards too of different kinds. St. Pierre 

 mentions a small and very handsome species in the island of Mauritius, 

 that pursues them into the houses, climbs up the walls, and even walks 

 over glass, watching with great patience for an opportunity of catching 

 them.^ The common snake also is said to receive part of its nutriment 

 from them. 



But to revert to insects as indirectly advantageous to us, by furnishing 

 food to fishes and birds, beginning with the former. Our rivers abound with 

 Jish of various kinds, which at particular seasons derive a principal part of 

 their food from insects, as the numerous species of the salmon and carp 

 genus. These chiefly prey upon the various kinds of Trichoptera, in 

 their larva state called case- or caddis-worms, and in their imago may-flies 

 (though this last denomination properly belongs only to the Sialis lutaria, 

 which generally appears in that month) and Ephemera. Besides these, 

 the waters swarm with insects of every order as numerous in proportion to 

 the space they inhabit, as those that fill the air, which form the sole 

 nutriment of multitudes of our fish, and the partial support of almost all. 



Reaumur has given us a very entertaining account of the infinite hosts 

 of Ephemerce that by myriads of millions emerge at a certain season of 

 the year from some of the rivers in France, which, as it is well worth your 

 attention, I shall abridge for you. 



These insects, in their first and intermediate state, are aquatic: they 

 either live in holes in the banks of rivers or brooks below the water, so 

 that it enters into their habitations, which they seldom quit ; or they 

 swim about and walk upon the bed of the stream, or conceal themselves 

 under stones or upon pieces of stick. Thougii their life, when they 

 assume the perfect state, is usually extremely short, some being disclosed 

 after sunset, laying their eggs and dying before sunrise ; and many not 

 living more than three hours ; yet in their preparatory state their existence 

 is much longer, in some one, in others two, in others even three years. 



The different species assume the imago at different times of the year; but 



' Span-man, ii. 180. 2 St. Pierre, Voij. 73. 



