MIGRATORY LOCUSTS 297 



Locusts are able to travel considerable distances, though how 

 far is quite uncertain. Accounts vary as to their moving by 

 night. It has, however, been recently proved that they do 

 travel at night, but it is not ascertained how long they can 

 remain in the air without descending. The ocean is undoubtedly 

 a, source of destruction to many swarms; nevertheless, they 

 traverse seas of considerable width. They have been known 

 to reach the Balearic Islands, and Scudder gives ^ a well-authen- 

 ticated case of the occurrence of a swarm at sea. On the 

 2nd of November 1865 a ship on the voyage from Bordeaux 

 to Boston, when 1200 miles from the nearest land, was in- 

 vaded by a swarm of locusts, the air and the sails of the ship 

 being filled with them for two days. The species proved to 

 be Acridium (Schistocerca) peregrinum. This is an extra- 

 ordinary case, for locusts do not fly with rapidity, being, indeed, 

 as we have remarked, chiefly carried by the wind. Possibly 

 some species may occasionally rest on the water at night, pro-" 

 ceeding somewhat after the fashion of the " Voetgangers " when 

 passing over rivers as described by Mrs. Barber. In Sir Hans 

 Sloane's history of Jamaica an account of an occurrence of this 

 kind is given on the authority of Colonel Keedham, who states 

 that in 1649 locusts devastated the island of Tenerife, that they 

 were seen to come from Africa when the wind was blowing thence, 

 that they flew as far as they could, then alighted on the water, 

 one on the other, till they made a heap as big as the greatest 

 ship, and that the next day, being refreshed by the sun, they took 

 flight again and landed in clouds at Tenerife. De Saussure says ^ 

 that the great oceans are, as a rule, impassable barriers, and that 

 not a species of the tribe Oedipodides has passed from the Old 

 World to the New. It is, however, possible that Acridium jpere- 

 grinum, of the tribe Acridiides, may have originally been an inhabi- 

 tant of America, and have passed from thence to the Old World. 



The species of Acridiidae that have been ascertained to be 

 migratory are not numerous.^ The most abundant and widely 

 <listributed of them is Pacliytylus cinerascens (Fig. 177), which 

 has invaded a large part of the Eastern hemisphere, extending 

 from the Atlantic Ocean to China. It exists in numerous spots 



^ CR. Soc. ent. Belgique, xxi. 1878, p. 5. 



- Addit. ad Prodro7num Oedipodiorum, 1888, p. 12. 



^ See Redtenbacher, Vher Warulerheuschrecken, in Jahresher. EcaUchxdc Budweis, 1893. 



