LOCUSTS. 401 



others were already hatched to march and glean after them. 

 Having lived near a month in this manner, they arrived at 

 their fall growth, and threw off their nympha state by cast- 

 ing their outward skin. To prepare themselves for this 

 change, they clung by their hinder feet to some bush, twig, 

 or corner of a stone ; and immediately, by using an undu- 

 lating motion, their heads would first break out, and then 

 the rest of their bodies. The whole transformation was 

 performed in seven or eight minutes ; after which they lay 

 for a small time in a torpid, and, seemingly, in a languish- 

 ing condition ; but as soon as the sun and the air had 

 hardened their wings by drying up the moisture that re- 

 mained upon them after casting their sloughs, they resumed 

 their former voracity, with an addition of strength and 

 agility. Yet they continued not long in this state before 

 they were entirely dispersed."* 



It is difficult to form an adequate conception of the 

 swarms of locusts which, in 1797, invaded the interior of 

 southern Africa, as recorded by Mr. Barrow. In the part 

 of the country where he was, the 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 carcases of locusts that floated on the suiface, 

 drowned in the attem^pt 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 precisely 

 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 larvee, 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 



* Sliaw's Travels, p. 287. 



2 D 



