MIGRATION AND DISPERSAL OF INSECTS '. COLEOPTERA. 357 



observed by a friend of his to fly on board a vessel 500 miles off the 

 west coast of Africa, and settle on his person ; a remarkable instance 

 of the power of so small a creature to traverse a long distance when 

 going with the wind. 



Baird observes {( 'i/d. of Xat. Sciours) that immense swarms of 

 ladybirds are sometimes observed in England, especially on the south- 

 eastern coast, they have been described as extending in dense masses 

 for miles, and the swarms are stated to consist of several species inter- 

 mixed. Kirby and Spence note {[ntrinl., ii., p. 9) that, in 1807, these 

 llights in Kent and Sussex caused no small alarm to the superstitious, 

 who tliought them the forerunners of some direful evil. They were, 

 however, but emigrants from the neighbouring hop-grounds, where, in 

 the larval state, they had been feasting upon the aphides. These 

 authors again note {loc. cit., 7th ed., p. 295) that the L'occinelUdae are 

 associated with aphides in their migrations. They see no other explana- 

 tion than that of migration to account for the vast number that are 

 sometimes, especially in the autumn, to be met with on the sea-coast 

 or the banks of large rivers. Many years ago, they state, those of the 

 Humber were so thickly strewn with Coccinella f^cpteiii punctata that it 

 was difficult to avoid treading upon them. Some years afterwards a 

 mixture of species was observed collected in vast numbers on the sand- 

 hills on the sea-shore at the north-west extremity of Norfolk. The Rev. 

 Peter Lathbury made long since a similar observation at Orford, on 

 the Suffolk coast, and about five or six years ago, the Coccinellids covered 

 the cliffs of all the watering-places on the Kentish and Sussex coasts, 

 whence they probably emigrated from the hop grounds. Whether the 

 aphides and their devourers cross the sea has not been ascertained ; 

 that the Cocci iwliidae attempt to do so is evident from their alighting 

 upon ships at sea as they themselves had witnessed. Walker writes : " I 

 am inclined to think that the propensity to migrate is developed 

 to some extent in the Coccinellidae, vast swarms of which, in 

 some favourable years, seem to make for the coast from inland, 

 often getting blown out to sea and perishing by millions upon 

 millions. In 1869 a very large swarm appeared quite sud- 

 denly in the Isle of Sheppey, completely smothering the grass on 

 the cliff-edges : these were carried out into the Thames' estuary by an 

 off-shore breeze, and the drowned insects were afterwards Avashed 

 ashore in such numbers as to form quite a bank along the beach for 

 several miles, in places an inch or more deep, and two or three inches 

 wide. Similar but slighter visitations of Coccinellidae have since 

 occurred here" {inlitt.). Douglas notes [Ent. Wk. Int.,]). 149) that, on 

 July 81st, 1858, swarms of At/ialia centifoliae, accompanied by hosts of 

 ladybirds, chiefly Coccinella l-}ninrtata, were observed between New- 

 haven and Seaford, the flight lasting for about half-an-hour in the after- 

 noon. In a discussion that took place on the evening of November 15th, 

 18()9,at thelilntom. Society of London, respecting the enormous numbers 

 of Syrphidsand ('orc/;;('///f/(/<' noticed during 1869, especially with refer- 

 ence to the supposed .migratory powers of these latter, thegcneral opinion 

 of the meeting was, that there was no necessity to suppose that immi- 

 gration took place, as the larvicwere extremely abundant locally in the 

 south of England a short time before the swarms of the perfect insects. 

 Thus Dunning observed {Tranfi. Knt. Soc. Jjondon, 1869, p. xxv) that 

 swarms of insects of various kinds " had been reported during the 



