236 THE entomologist's record. 



Migration and Dispersal of Insects : Lepidoptera. 



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



Whatever interest may attach to what we may term the internal 

 migration oiAnosia archippuH Avithin the Near ctic region, much greater 

 interest is felt in its movements to distant parts of the world. Its 

 wandering habits have led it to seek other shores, and during the last 

 half century it has practically encircled the globe. Before, however, 

 dealing with this, one may note that Walker observes [Fynt. Mo. Ma//., 

 xxii., p. 217) that at Monte Video the Avell-marked form eripjnis occurs 

 in December, and that in 1881, at Callao, A. archippm was one of the 

 commonest butterflies of the district, and was especially abundant in 

 January and February, and scarcest in July, though one could make 

 sure of seeing the imago on the wing almost any day throughout the 

 year. Apart from the range of the southern var. crippus, the insect 

 would appear to cover in America about 90° of latitu.de, since 

 Walker records it from Bolivia and the Amazon district, and specimens 

 have been captured at Moose Fort 50° 20' N. lat. and at Esquimault, 

 in Vancouver Island, at about the same latitude. 



No doubt can exist that it was originally an American insect, and 

 it appears to have reached the Hawaiian Islands, some 2000 miles from 

 its American home, about 1850, contemporaneously Avith the introduc- 

 tion of its food-plant, the Asvlepiaa. In 1857 it appears to have 

 reached Ponape, one of the Caroline Islands, about 2000 miles from 

 the HaAvaiian Islands. In 1863 it Avas taken in the Friendly Islands ; 

 in 1867 in Tutiulla, one of the Samoan Islands, and in 1869 Avas 

 observed in tAVO others, Upolu and Savaii. In 1868 it Avas seen in 

 the Pacific Ocean, 500 miles from land. In 1870 it Avas found in the 

 Society Islands; Miskin first recorded it from Australia in 1870, Avhen 

 it appeared in Queensland ; in 1872, it Avas noted at Melbourne, but 

 has noAV spread throughout all the Avarmer parts of the island, and has 

 also been taken in Tasmania. W^alker records it as having occurred 

 in thousands in the SandAvich Islands, in 1873, and notes it as being 

 the commonest butterfly in the Marquesas, Avhere it Avas unknoAvn 

 before 1860. In the Society Islands and the Cook and Hervey Islands 

 it is common, and has e\'en reached the remote little island of Oparo 

 or Eap-ci far aAA'ayto the southAvard; it is also established in the Malay 

 Archipelago. He further notes that, in 1883, during the cruise of the 

 "Kingfisher" among the South Sea Islands, this was usually the 

 first butterfly observed, and in some of the islands Avas exceedingly 

 abundant considering hoAV recently it had been introduced. MatheAv 

 says that it is found through the Samoan, Friendly and Fiji Islands, 

 being especially abundant in the latter, has reached the North Island 

 of NeAV Zealand, as Avell as Norfolk Island, Avhilst in NeAV Caledonia, 

 Avhere it became very abundant, it has practically exterminated itself 

 by the destruction of the food-plant (an introduced Aveed) by the larvae. In 

 the NeAV Hebrides, Solomon Islands, and NeAv Guinea, it has become 

 common, and Semper has recorded it for Celebes, Avhilst Kirby says 

 that it has been taken in Java, and a specimen Avas captured on April 

 19th, 1889, in the Straits of Malacca, betAA-een Penang and Singapore. 

 So much for its AvestAvard migration. 



With regard to its spread in an easterly direction, Ave may first 

 state that it is abundant in the West Indies and has, for some years 



