320 NATURAL HISTORY OF THE BERMUDAS. 



sunshine ; and that they move in a direct course at the rate, 

 more or less, of fifteen miles an hour, a tolerable idea may 

 be formed of the manner in which the millions of Terias 

 lisa, mentioned by Mr. Jones, have been gathered together 

 on the land, and swept six hundred miles away from it 

 over the vast Atlantic. 



It must be obvious to everyone that diurnal Lepidoptera 

 are not seen during the night time, neither do they leave 

 their retreats during wet and stormy weather, consequently 

 these Butterflies would be found on the wing only in the 

 daytime, and it is reasonable to suppose they would come 

 forth on the first appearance of fine weather after a 

 storm. 



The outer circumference of a tropical storm passing over 

 many miles of country would thus come in contact with 

 large numbers of Butterflies on the wing, hurrying them 

 away, helplessly down wind, in a continuous and compara- 

 tively narrow belt, or zone, without injury to themselves — 

 for it may be safely inferred that, like aeronauts in the car 

 of a balloon, Butterflies on the wing under such circum- 

 stances would be insensible to the rapidity with which 

 they were floating through the atmosphere. In this 

 manner might large numbers travel from the shores of 

 America to the distant islands of Bermuda in ten or twelve 

 hours — measured by the speed of an ordinary balloon — 

 there to be cast adrift by the onward progress of the storm. 



That such is the mode in which large flights of Lepi- 

 doptera are assembled together on the land is borne out 

 by the evidence of various writers. 



It is idle to suppose that Butterflies instinctively migrate 

 from one locality or country to another. When seen con- 

 gregating in immense numbers on land or sea, there is 

 every reason to believe they have been gathered together 

 in the manner here stated. 



