

THE MIGRATIONS OF INSECTS 67 



crossing towards land, and the case of these ladybirds 

 seems much the same. Sometimes the drowned in- 

 vaders consist of black flocks of the tiny turnip beetles, 

 which lie on the waves like soot. Fishermen who 

 spend much of their time off the mouth of the Wash 

 and the north Norfolk coast have told the writer 

 that butterflies constantly visit their boats, flying In 

 from the sea ; and from time to time blue butterflies 

 are seen lying at short intervals, from yard to yard, 

 along miles of the sea-fringe of sand on the Lincoln 

 coast. 



The painted lady butterflies appear to assemble for 

 migration as swallows do. Great columns of them 

 many yards wide have been seen flying in a given 

 direction. 



A locust alighted on the deck of the Beagle 

 at a distance of three hundred and seventy miles 

 from land. If an insect only four inches long 

 can make such a flight, no limits can be set to the 

 possible migrations of locusts. They cross seas and 

 even mountains. Some years ago they appeared near 

 Darjeeling. Whence they came is not precisely 

 known. But it is believed that they crossed the 

 Himalayas from Thibet. The invasions of locusts 

 are best remembered when for some reason unknown 

 they decide to leave the regions over which their 

 flight is generally taken, and to make a vast aerial 

 trek into others. Such invasions naturally attract 

 great attention. The records remain, emphasised by 

 the actual losses inflicted, and not infrequently by 

 more serious misfortunes. 



