156 THE ENTOMOLOGIST. 



Extracts from Notes on Locusts. By F. Walker, Esq. 



The observations of Lallemant show that the locust, 

 Acridium peregrinum, inhabits the fertile region in the in- 

 terior of Africa ; that the swarms cross the great desert, or 

 the Sahara, by means of the favourable influence of the 

 Sirocco; that this wind is prevalent for a day or two before 

 they come to Algeria ; that they often fly at a great height, 

 and are thus enabled to cross the Atlas range ; that the time 

 of their coming varies from April to June ; that their coming 

 is not annual, but irregular ; that large numbers are some- 

 times carried by the wind into the sea, where they have been 

 observed to form a yellow line of sixty miles in length ; that 

 the number on land is not thereby apparently diminished ; 

 that each female deposits at least eighty-five eggs, which are 

 hatched in a month ; that this second generation is some- 

 times suppressed by turning over the soil, and thus exposing 

 the ej^gs to the destroying heat of the sun, and by the tough 

 and dry vegetation in the later time of the year, which food 

 is not suited to the softness of the jaws of the young locusts ; 

 that the latter have nevertheless sometimes thriven, as may 

 be supposed by the fact that a person has destroyed about 

 9,100,000 individuals of the second generation on his land 

 at one time. 



The most generally believed opinion, with regard to 

 Acridium peregrinum and Pachytylus migratorius, is that 

 they come from the Soudan, the equatorial region of Africa. 

 The summer swarms, hatched in the sandy districts, travel, 

 half to the South, half to the North, in search of more abun- 

 dant food than that in the desert. The life of these locusts 

 beyond the egg state does not last beyond fifty days or 

 thereabouts, and those that leave the Soudan do not reach 

 Algeria, but oviposit and perish in transit thither ; and 

 the swarms of the next generation possess themselves of 

 Algeria, and lay eggs there: during six years these eggs did 

 not hatch, but in 1866 the eggs then laid were hatched, and 

 the ensuing larva3 committed greater ravages than the adults, 

 and were full-grown towards July. In August all traces of 

 locusts have generally disappeared. A cloud of locusts 

 arrived at Algiers on the 6th of January, 1867, a season of 

 the year in which they had never been previously seen. 



