OETHOPTEEA. 307 



In the environs of Algiers alone were destroyed, in 1845, 369 

 quintals of locusts. It is computed that four hundred locusts go to 

 a kilogramme. This gives, then, a total of 14,760,009 insects 

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

 each female lays on an average 70 eggs, the result we arrive at is, 

 that this stopped the production of 516,600,000 larvaD on the terri- 

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

 in 1866 was as disastrous as that of 1845. It was in the 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 of the 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. Yery 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 mul- 

 titudes, 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 them- 

 selves 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 Mostaganem, they attacked the tobacco, the vines, the 



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