SOUTHERN AFRICA. 21-5 
of corn. The insect seems constantly to be in motion and to 
have some object in view. When on a march during the day 
it is utterly impossible to turn the direction of a troop, which 
is generally the same as that of the wind. The traces of their 
route over the country remain for many weeks after they have 
passed it, the surface appearing as if swept by a broom, or as 
if a harrow had been drawn over it. Towards the setting of 
the sun the march is discontinued, when the troop divides in- 
to separate companies, which surround the small shrubs, or 
tufts of grass, or ant-hills, and in such thick clusters that they 
appear like so many swarms of bees ; and in this manner they 
rest till day-light, it is at such times only, when they are thus 
formed into groupes, that the farmers have any chance of de- 
stroying them, which they sometimes effect by driving among 
them a flock of two or three thousand sheep, by whose rest- 
lessness they are trampled to death. 
Luckily the visits of this gregarious insect are but period- 
ical, otherwise the whole countiy must inevitably be deserted, 
as wherever they appear they rest, as the prophet in Holy 
Writ hath said, " upon all thorns and upon all bushes." 
Even at this time the cattle in many parts of Sneuwberg are 
starving for want of food. The present year is the third of 
their continuance, and their increase has far exceeded that 
of a geometrical progression whose ratio is a million. For 
ten years preceding their present visit, the colony had been 
entirely free from them. Their last departure was rather sin- 
gular. All the full-grown insects were driven into the sea 
by a tempestuous north-west wind, and were afterwards cast 
upon the beach, where it is said they formed a bank of three 
