KIRBY AND SPENCE 213 



over it in an hour, and calculated that 65,000 butter- 

 flies had passed over every hundred yards during 

 the flight, which lasted from nine o'clock in the 

 morning to a little after five in the afternoon. The 

 breadth of the migration column was about three 

 miles. On the following day they continued for about 

 seven , to eight hours passing in the same numbers, 

 then the numbers began to decline, and on the third 

 day the whole migration finished. 



During the whole time of my watching, the butter- 

 flies kept always so close to the surface as to be 

 almost touching the grass, travelling always at the 

 same swift rate of speed, and never did I see one 

 alight to rest. 



It cannot be supposed that this migration of 

 butterflies, travelling in their millions over a vast 

 tract of country, had a different cause to that of 

 bird migration going on at the same time over the 

 same tract and in the same direction. 



Migrations of this character of butterflies and many 

 other insects have been witnessed and described by 

 hundreds of observers, so that there is an abundance 

 of material for the thinkers to work on, but so far 

 the only speculation on the subject I have come 

 across is in Kirby and Spence's great work: I find 

 it in the early unabridged editions in four volumes. 

 They speculate as to the reasons which induced the 

 Creator to endow these insects — butterflies, beetles, 

 dragon-flies, bugs, locusts, aphides, and others — with 

 such an instinct, seeing that they are only influenced 

 by it occasionally and that it invariably leads to the 



