188G.J ' 221 



ber 6tli of that year. This is now in the British collection at the 

 Natural History Museum, South Kensington, and is a very fine example 

 of the ordinary North American type. Another was taken at Hay ward's 

 Heath, Sussex, in the autumn of the same year (Entomologist, vol. ix, 

 p. 267). In September, 1877, a specimen was captured by M. Grassal 

 in La Vendee (Petites Nouvelles Entomologiques, IT, pp. 253, 254), 

 the only record I can find of its occurrence on the European continent. 

 A specimen is recorded by Mr. J. Jenner Weir (Entom. vol. xix, p. 12), 

 as having been taken near Snodland, Kent, on September 21st, 1881 ; 

 but the number seen and caught last year far exceeds all that have been 

 previously noted. A. round dozen, at least, have been recorded from 

 our southern counties, Cornwall contributing quite half the number, 

 though Devon, Dorset, and the Isle of Wight have also been favoured 

 with the visits of the imposing stranger (Ent. Mo. Mag. vol. xxii, pp. 

 134, 161, 211 ; Entomologist, vol. xviii, p. 305). 



The question naturally arises : What has caused this truly won- 

 derful extension of the range of Anosia Flexippus ? We may, I think, 

 dismiss the idea that the insect and its chief food-plants (noxious and 

 poisonous weeds) may have been voluntarily transported to new lands. 

 The seeds, however, of Asclepias curassavica are eminently fitted for 

 wide dispersal, being very minute, and enveloped in a great quantity 

 of light cottony down, and it is quite possible that they may have, iu 

 the first instance, been carried unobserved to the Sandwich Islands 

 through the medium of commerce. Thus the first great gap of 2350 

 miles in extent (measured from the nearest point of the American conti- 

 nent) may have been bridged over by the plant. As for the butterfly, 

 its great hardiness and almost complete exemption from the attacks of 

 enemies, joined with its well-known migratory propensities and habit 

 of assembling in great swarms, render its chances of wide dispersal 

 and ready adaptation to a new home especially favourable. It is won- 

 derful to what great distances butterflies and moths are blown out to 

 sea, and in what good condition they remain, all things considered. 

 Mr. Mathew informs me that he has often seen Anosia Plexippus 

 " flying at a great height above the ship, sometimes more than 200 

 miles from the nearest land. During a cruise between New Caledonia 

 and the Solomon Islands, they were to be seen every day, often in 

 numbers. This looked as if a steady migration was taking place, and 

 the S.E. trade wind, which was blowing strongly at the time, was 

 greatly in favour of the butterflies accomplishing their journey in 

 safety." I once saw Danais Chrysippus (a much smaller and less 

 powerful insect than Flexippus,) flying about the ship when she was 



