FORMS INJURIOUS TO HUMAN INDUSTRIES 



357 



regarding such forms will give an idea of the possibilities: — "In 

 countries that are liable to their visitations they have a great 

 influence on the prosperity of the inhabitants, for they appear 

 suddenly on a spot in huge swarms, which, in the space of a 

 few hours, clear off all the vegetable food that can be eaten, 

 leaving no green thing for beast or man. It is difficult for those 

 who have not witnessed a serious invasion to realize the mag- 

 nitude of the event. Large swarms consist of an almost incal- 

 culable number of individuals. A writer in Nature [Carruthers, 

 1889] states that a flight of locusts that passed over the Red Sea 



Fig. 1255. — Larva and Adult Female of the Migratory Locust {Sckistocerca ^eregrina 



in 1889 was 2000 square miles in extent, and he estimated its 

 weight at 42,850 millions of tons, each locust weighing -^ of an 

 ounce. A second similar, perhaps even larger, flight was seen 

 passing in the same direction the next day. That such an esti- 

 mate may be no exaggeration is rendered probable by other 

 testimony. From official accounts of locusts in Cyprus we find 

 that in 1 881, up to the end of October, 1,600,000,000 egg-cases 

 had been that season collected and destroyed, each case containing 

 a considerable number of eggs. By the end of the season the 

 weio-ht of the eeo-s collected and made away with amounted 

 to over 1300 tons, and, notwithstandmg this, no less than 

 5,076,000,000 egg-cases were, it is believed, deposited in the 

 island in 1883. When we realize the enormous number of indi- 

 viduals of which a large swarm of locusts may consist we can see 

 that famine is only a too probable sequence, and that pestilence 

 may follow — as it often has done — from the decomposition of the 



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