12 



IMPERFECT SOCIETIES OF INSECTS. 



coast, I have, at certain times, seen innumerable insects upon 

 the beach close to the waves, and apparently washed up by 

 them. Though wetted, they were quite alive. It is remark- 

 able, that of the emigrating insects here enumerated, the 

 majority — for instance, the lady -birds, saw-flies, dragon-flies, 

 ground-beetles, frog-hoppers, &c, are not usually social 

 insects, but seem to congregate, like swallows, merely for 

 the purpose of emigration. What incites them to this is one 

 of those mysteries of nature, which at present we cannot 

 penetrate. A scarcity of food urges the locusts to shift their 

 quarters, and too confined a space to accommodate their 

 numbers occasions the bees to swarm; but neither of these 

 motives can operate in causing unsocial insects to congregate. 

 It is still more difficult to account for the impulse that urges 

 these creatures, with their filmy wings and fragile form, to 

 attempt to cross the ocean, and expose themselves, one would 

 think, to inevitable destruction. Yet, though we are unable 

 to assign the cause of this singular instinct, some of the 

 reasons which induced the Creator to endow them with it 

 may be conjectured. This is clearly one of the modes by 

 which their numbers are kept within due limits, as, doubtless, 

 the great majority of these adventurers perish in the waters. 

 Thus, also, a great supply of food is furnished to those fish in 

 the sea itself, which at other seasons ascend the rivers in 

 search of them ; and this probably is one of the means, if not 

 the only one, to which the numerous islands of this globe are 

 indebted for their insect population. "Whether the insects I 

 observed upon the beach, wetted by the waves, had flown 

 from our own shores, and falling into the water had been 

 brought back by the tide ; or whether they had succeeded in 

 the attempt to pass from the continent to us, by flying as far 

 as they could, and then falling had been brought by the 

 waves, cannot certainly be ascertained ; but Kami's observa- 

 tion inclines me to the latter opinion. 



The next order of imperfect associations is that of those 

 insects which feed together : these are of two descriptions ; 

 those that associate in their first or last state only, and those 

 that associate in all their states. The first of these associ- 

 ations is often very short-lived : a patch of eggs is glued to 



