DRAGON-FLIES 211 



hensively at what would happen in the following 

 summer, when these millions of packets of little 

 yellow eggs would hatch and the young arrive at 

 maturity, since one of these huge insects would 

 devour as much green-stuff in a day as half a dozen 

 grasshoppers. And grasshoppers were bad enough. 

 But the eggs never hatched; the locusts had flown 

 too far south, where there were occasional sharp 

 frosts in the winter, and the eggs had probably been 

 spoilt by the cold. 



As to dragon-flies, great migrations of two or three 

 of the large species were common on the pampas, 

 always in a north-east direction, since the insects 

 invariably appeared flying before the south-west 

 wind, called pampero^ a wind that in summer, as a 

 rule after a spell of hot weather, springs up suddenly 

 and blows with extreme violence. From a minute or 

 two to as much as fifteen or twenty minutes before 

 the wind struck, the dragon-flies would appear flying 

 at their utmost speed, so that when out on the plain 

 on foot or horseback one could not tell what those 

 swift creatures were that came flashing and rustling 

 past one's face. They always appeared to be in a 

 panic, and if the wind was close behind, on coming 

 to a grove or plantation they would rush into it for 

 shelter and there remain, and on the following morn- 

 ing they would be seen hanging from the trees, 

 clinging together in masses, like swarms of bees, and 

 the masses would sometimes cover entire trees as 

 with a brown and crystal drapery. These panic 

 rushes from the wind are in a sense migrations, but 



