MIGRATION AND DISPERSAL OF INSECTS ! ORTHOPTERA. 119 



and, as the breeze freshened during the day the work of destruction 



increased. • r i t 



In 1891 considerable damage was done by a species of locust 

 (Chortoloqa amtmlh) in South Australia, which migrated south in 

 search of food. This swarm travelled scattered, and not very high, 

 never in clouds. There are a considerable number of records of 

 mi^ratin,"- swarms of locusts that have been observed in the antipodes. 

 ''No chapter on the migration of locusts could be written Avithout 

 reference to Darwin's own observations on the subject. Ho writes 

 [Voucvie of the Becuilc) :— " Shortly before we arrived at Luxan wo 

 observed "to the south a ragged cloud of a reddish-brown colour. 

 At first we thought it was smoke from some great fire on the plains, 

 but we soon found that it was a swarm of locusts. They were flying 

 northward, and, with the aid of a light breeze, they overtook us at a 

 rate of ten or fifteen miles an hour. The main body filled the air from 

 a heio'ht of twenty feet to that, as it appeared, of tAVo or three 

 thousand feet above the ground, and ' the sound of their wmgs was as 

 the sound of chariots of many horses running to battle, or rather, i 

 should say, like a strong breeze passing through the rigging of a ship. 

 The sky seen through the advanced guard, appeared like a mezzotint 

 eno-ravin'o-, but the main body was impervious to sight ; they were not, 

 however,' so thick together but that they could escape a stick waved 

 backwards and forwards. When they alighted they were more numerous 

 than the leaves in a field, and the surface became reddish ins cad of 

 bein" "reen. The swarm having once alighted, the individuals tiew 

 froin stde to side in all directions. Locusts are not an uncommon pest 

 in this country ; already, during this season, several smaller swarms 

 had come up from the south, where, as apparently m all other parts ot 

 the world, they are bred in the deserts. The poor cottagers m vain 

 ■ attempted, by lighting fires, by shouts and by waving branches, to 

 avert the attack. This species of locust closely resembles, and, perhaps, 

 is identical with the famous Gnjllus vwjratonm of the J^ast. ine 

 Gnjllas vwiratorius here referred to by Darwin is probably the species 

 known SbS S. pa ranense. _ 



Darwin further relates (Oruiin of Species, p. 329) that m 184-1 

 swarms of locust, visited Madeira. " They were in countless numbers, 

 as thick as the flakes of snow in the heaviest snowstorm, and extended 

 upward as far" as could be seen with a telescope, during two or t^ree 

 days they slowly careered round and round_ in an immense ellipse at 

 least five or six miles in diameter, and, at night alighed on the taller 

 • , which were completely coated with them. They f- disappeared 

 over the sea as suddenly as they had appeared, and h-MC not since 



"^^f remlrkable-Iwarm of a species of cricket (O.-.^.s) is r^orded in 

 Insect Life. The account states that on September 9th and 10th, 1890, 

 at Gainesville, Texas, a flight of crickets was observed accompanied 

 by a small da;k beetle, about half an inch m length, ;vb|ch proved to 

 be Ihuwdus .imris. They appeared to fly m an easterly direction. At 

 the s^ne time flights wer^ imported from Dallas, Texas, with a remark 

 as to their being attracted by the electric ights, and m ^^ aco the stone 

 base of the city hall was black with their ^^^o^'"^^^,"^'^^^,^^' , J* T, 

 stated that there were enough here to make several ca t oads^ All 

 night restaurants were compelled to close. Large quantities of the 



