248 INSECT TRANSFORMATIONS. 



whole surface of the ground, for an area of nearly 

 two thousand square miles, might literally be said 

 to be covered with them. The water of a very wide 

 river was scarcely visible, on account of the dead car- 

 cases of locusts that floated on the surface, drowned 

 in the attempt to come at the reeds that grew in it. 

 They had devoured every blade of grass, and every 

 green herb, except the reeds. But they are not pre- 

 cisely without a choice in their food. When they 

 attack a field of corn just come into ear, they first, 

 according to Mr, Barrow, mount to the summit and 

 pick out every grain before they touch the leaves and 

 stem, keeping the while constantly in motion, with 

 the same intent of destruction always in view. When 

 the larvae, which are much more voracious than the 

 perfect insects, are on a march during the day, it is 

 utterly impossible to turn the direction of the troop, 

 and this seems usually to correspond with that of the 

 wind. Towards the setting of the sun the march is 

 discontinued, when the troop divides into companies 

 that surround the small shrubs, or tufts of grass, or 

 ant-hills, in such thick patches, that they appear like 

 so many swarms of bees ; and in this manner they 

 rest till day-light. At these times it is that the farm- 

 ers have any chance of destroying them ; this they 

 sometimes effect by driving among them a flock of 

 two or three thousand sheep, by whose lestiessness 

 great numbers of them are trampled to death. The 

 year 1797 was the third of their continuance in Sneuw- 

 berg ; and their increase had been more than a mil- 

 lion-fold from year to year. 



This district, however, had been entirely free from 

 them for ten years preceding their visit in 1794. 

 Their former exit was singular: all the full-grown 

 insects were driven into the sea by a tempestuous 

 north-west wind, and were afterwards cast up on the 

 beach, where they formed a bank of three or four feet 



