AND AT SEA 191 



we cannot suppose that the insects were blown off the 

 land, but we must conclude that they voluntarily took 

 flight." 



Observers in India and other tropical regions 

 have noticed on many occasions vast swarms of 

 Pierinae moving in a line along the sea coast, and. 

 occasionally such swarms have been seen in similar 

 situations in temperate regions ; tluis Dr. Schiilte 

 relates that in a dead calm off Nordeney in the 

 Baltic Sea, he steamed for three hours and a dis- 

 tance of thirty miles through a continuous flock of 

 the Cabbage butterfly (Pieris rapae) from ten to 

 thirty miles from the main land and only five miles 

 less than that from the nearest island ; afterward 

 the shore was found strewn with their dead bodies. 

 And on our own side of the ocean we have a curi- 

 ous instance related of the Little Sulphur (Eurema 

 lisa) by Mr. J. M. Jones, who states that early 

 one October morning several persons living on the 

 northern side of the main island of Bermuda per- 

 ceived what they thought to be a cloud coming 

 from the northwest, which turned out to be " an 

 immense concourse of small yellow butterflies, 

 which flitted about all the open grassy patches and 

 cultivated grounds in a lazy manner, as if fatigued 

 after their long voyage over the deep," and fisher- 



