MIGBATION AND DISPERSAL OF INSECTS : LEPIDOPTERA. 13 



Migration and Dispersal of Insects : Lepidoptera. 



By J. W. TUTT, F.E.S. 



We have already shown that Ijutterflies and moths have often been 

 observed and captured at considerable distances from land. The habit 

 of flying out to sea is probably much more frequent than is generally 

 supposed. Walker reports that at Colombo, on April 20th, 1890, the 

 forenoon being fine and hot, quite a number of butterflies came off and 

 flew about the ship, but they were wild and difficult to approach. 

 Among these several male specimens of Oniithoptera pompeius were 

 recognised (one secured), Papilio sarpedon, P. pammon, P. diphilm, P. 

 pohjmneMor, MessaniK enjmanthis, &c. Mr. Manger has an example of 

 Macror/lofisa stellatariDii taken in the Eed Sea, one of Patula macrops in 

 the Straits of Malacca, ten miles from land, in June, 1894, an Ophideres 

 fullonica in the China Sea, 100 miles from land, both the latter by Cap- 

 tain Walker, Deilephila alccto, that came on board the s.s. Mallard in the 

 Mediterranean, DeilepJala livornica and Chocrocampa celerio captured in 

 the Eed Sea, Abraxas phantes off Cochin China, 100 miles from land, 

 in June, 1894, Euchera capitata taken in the China Sea, on the 

 Kara, in July, 1894, by Captain Walker, and Marr/arodes unioyialis 

 captured off the coast of Algiers. We ourselves saw a specimen of 

 what appeared to be Pieris rapae heading straight for the coast at Folke- 

 stone, as we were crossing to Boulogne on July 26th, 1899, when the 

 boat Avas about halfway across the Straits, and there is a note {Entom. 

 Record, xi., p. 297) of Pyramcis atalanta having been captured (many 

 seen) in the Atlantic Ocean, some 500 miles from the Lizard. These, 

 however, are more or less isolated examples, and it may be well to 

 review the evidence available of larger or smaller flights of lepidoptera 

 that have been observed on what must certainly be considered migration 

 flights. 



Kapp observes (Xatnrforscher, vi., Ill) that on a calm sunny day he 

 noticed a prodigious flight of Pieris brassicae, that passed from north- 

 east to south-west, the flight lasting two hours. Kahn also records 

 [Travels, i., 13) a flock of this species about halfway across the English 

 Channel. Tindley writes {Piun. Milit. Chronicle, 1815, p. 452) that in 

 Brazil, at the beginning of March, 1803, there was, for many days 

 successively, an enormous flight of white and yellow butterflies, prob- 

 ably of the same tribe as the cabbage butterfly ; they were never 

 observed to settle, and proceeded in a direction from north-west to 

 south-west, no buildings seemed to stop them from steadily pursuing 

 their course, Avhich, " being to the ocean, at only a short distance, they 

 must have reached to perish." A migratory column of Pyrameis cardid, 

 of from 10ft. -15ft. in breadth, was observed in the Canton Vaud 

 (Switzerland), in 1836, the flight occupying two hours on its passage. 



The reports of the lighthouse keepers, furnished to a committee 

 appointed by the British Association for the advancement of Science, 

 show some very definite results. Some of the extracts taken from them 

 are as follows : — 



Hanois Lighthouse (to the west of Guernsey), the extreme westerly point of the 

 Channel Islands, in a direct line between the N.W. coast of France and the S.W. 

 coast of England. 1882. — " June and July : Flights oi Plusia fjamma." 1885. — 

 " September 13th : Wind S.E., sky cloudy. Silver Gamma moths all evening round 

 lantern." 1886. — "October 31st, 8.0 p.m. A quantity of Silver Gamma moths 

 also a few brown ones but smaller than the Gamma." 



