132 LECTURE X. 



witnessed a migration of butterflies, which were 

 far distant from any land, and on a subsequent 

 occasion a migration of humming-birds. Change 

 of weather, no doubt, produces migratory im- 

 pulses a fact which some of you fishermen are 

 acquainted with. 



Some few years ago immense cloud-like 

 swarms of dragon-flies passed in rapid succes- 

 sion over a town in Germany. Their progress 

 was from south-by-west to north-by-east, some 

 flying high and others low, and they struck 

 against the windows of houses situated on emi- 

 nences. We are not visited in this country by 

 locusts, which commit such vast injuries on 

 crops in the East. When the migratory im- 

 pulse is on them they swarm in vast numbers, 

 taking long flights, and sometimes alighting in 

 the sea and perish. 



Some animals change their quarters (it may 

 be called migration) for unaccountable reasons. 

 For instance, the badger, which is a soli- 

 tary animal, and once very numerous in this 

 country, would assemble to the number of nine 

 or ten, and travel by night to some other loca- 

 lity. If any one happened to disturb them in 

 their progress, he was attacked with the greatest 



