308 THE INSECT WORLD. 



of the Commandant de la Place of Philippeville, M. Levaillant, a 

 column of locusts alighted in the country round about that town on 

 the 1 8th of March, 1845, which extended from 30 to 40 centimetres, 

 and the locusts were found heaped upon the ground to the height of 

 three decimetres. 



In the environs of Algiers alone were destroyed, in 1845, 

 369 quintals of locusts. It is computed that 400 locusts go to a 

 kilogramme. This gives, then, a total of 14,760,000 insects 

 destroyed. As in this number half were probably females, and as 

 each female lays on an average seventy eggs, the result we arrive at is, 

 that this stopped the production of 516,600,000 larvae on the 

 territory of Algiers alone. The invasion of locusts which took place 

 in 1866 was as disastrous as that of 1845. It was m tne month of 

 April, 1866, that the vanguard of these destructive insects appeared. 

 Debouching through the mountain gorges and through the valleys, 

 into the fertile plains near the coast, they alighted first on the plain ot 

 Mitidja and on the Sahel of Algiers. Their mass, at certain points, 

 intercepted the light of the sun, and resembled those whirlwinds of 

 snow which, during the storms of winter, hide the nearest objects 

 from our view. Very soon the cabbages, the oats, the barley, the 

 late wheat, and the market-gardeners' plants, were partly destroyed. 

 In some places the locusts penetrated into the interiors of the houses. 

 By order of the government of Algiers the troops joined the colonists 

 in combating the plague ; and the Arabs, when they found that their 

 interests were suffering, rose to lend their aid against the common 

 enemy. Immense quantities of locusts were destroyed in a few days ; 

 but what could human efforts do against these winged multitudes, 

 who escape into space, and only abandon one field to alight in the 

 next? 



It was impossible to prevent the fecundation of these insects. 

 The eggs quickly producing innumerable larvae, the first swarms 

 were very soon not only replaced, but multiplied a hundredfold by a 

 new generation. The young locusts are particularly formidable on 

 account of their voracity. These hungry masses threw themselves 

 upon everything which was left by those which went before them. 

 They choked up the springs, the canals, and the brooks ; and it was 

 not without a great deal of trouble that the waters were cleared of 

 these causes of infection. Almost at the same time the provinces of 

 Oran and of Constantine were invaded. At Tlemcen, where within 

 the memory of man locusts had never appeared, the ground was 

 covered with them. At Sidi-bel-Abbes, at Sidi-Brahim, at Mos- 

 taganem, they attacked the tobacco, the vines, the fig-tree, and even 



