xc, 



in their appearance. One of these plagues, in 1784, in Sooth 

 Africa, is said to hare been so extensive that an area of 

 2,000 square miles was covered with the locusts, which destroyed 

 everything green. A north-west wind drove them into the sea, 

 where they formed a bank three or four feet high along 50 miles 

 of the shore. Immense numbers of people have perished in 

 similar visitations at different times, both from the famines 

 caused by the ravages of the locusts and also from pestilences 

 generated by their dead bodies, when accumulated in the 

 manner described above, 



Africa is, par exedknce, the home of the locusts of the Old 

 World, bttt they have at times caused great devastation in parts 

 of Asia, from Arabia to China, India is sometimes visited by 

 enormous flights of these insects, as in 187$, when the Madras 

 Presidency suffered greatly from the attacks of the same species 

 as that specially observed in Algeria, In Europe locusts seem 

 occasionally to migrate northwards in great numbers, and 

 spread over many countries, stragglers sometimes reaching our 

 own shores. In A,, 591 and 1478 Italy is recorded as having 

 suffered greatly, Russia in 1650, Spain in 1841 ; bttt the fact that 

 they become much more frequent, as records are better kept, 

 suggests that these are but a few out of many such plagues in 

 earlier times. In North America, where entomology is much 

 better looked after by the State than in most countries, it would 

 seem that serious attacks occur on an average about once in 

 eleven years, depending upon the specially favourable conditions 

 of the season for the production of large numbers of the perfect 

 insects. Very extensive reports have been published on the 

 subject in the year 1878 and subsequently. The chief species 

 concerned is Melanoplu$ fprelut, the Rocky Mountain locust, 

 which migrates from Montana towards the south and south-east, 

 sometimes in immense and most destructive swarms. These 

 locusts have been known to travel as much as 2,000 miles in 

 their migration, starting in July, flying like the Algerian 

 Schiffacma peregrina during the daytime only. It seems 



