284 [October, 



the Pacific. It is highly probable that it owed its first introduction to 

 the Hawaiian Islands to similar agencies, and that its appearance in 

 Europe is due to the same cause." 



As far as I am aware, we have no proof of the " aestivation " of 

 this, or indeed of any butterfly, and I much doubt the probability of 

 the perfect insect remaining cpiieseent on or in any part of a ship in 

 the tropical regions, as suggested above by Dr. Scudder. In a voyage 

 of any length, too, it would lie always exposed to the risk of being 

 sooner or later blown away from the vessel. Darwin (I.e., p. 158, 

 foot-note) writes, " The flies which frequently accompany a ship for 

 some days on its passage from harbour to harbour wandering from 

 the vessel, are soon lost, and all disappear." On the other hand, a 

 ship in mid-ocean may well form as welcome a resting-place for a 

 wandering butterfly as for a migrating bird, and may be at times the 

 means of enabling either to reach a new land. 



The probability of Banaida ^/ezipjjtts being transported in its 

 early stages is, I think, even less than in the case of the imago. In 

 the warmer parts of its range, the whole of its transformations, from 

 the laying of the egg to the emergence of the perfect insect, are effected 

 in six weeks or even less (Ent. Mo. Mag., vol. XXII, p. 218), the eggs 

 hatching in from four or five days to a week, and the pupa state lasting 

 two or three weeks at most. Thus in the event of the pupa (c/. Seitz, 

 Macro-Lep., Pal. Region, I, p. 77, footnote), or even the food-plant with 

 eggs attached, having been included in " bales of hay " these eggs would 

 stand a very small chance of remaining unhatched on a sea voyage of 

 any length, and the young larvae would almost inevitably perish. The 

 integuments of the larva, unlike those of the imago, are very soft and 

 tender, and readily liable to mechanical injury. Again, no one who 

 has ever handled a living pupa or the filmy transparent shell of one 

 that has been vacated by the perfect insect, will be likely to admit the 

 possibility of its surviving the rough treatment it would necessarily 

 receive if included by accident with merchandise on board ship. This 

 also appears to me to dispose of the suggestion by Mr. Distant (I.e., 

 pp. 97-8) as to the possibility of the butterfly, in any of its stages, 

 being conveyed to distant lands by the agency of trees or other 

 " natural debris " borne on the great currents of the ocean, however 

 efficacious such means may be in the case of other creatures of a more 

 hardy nature. 



From my further experience of Banaida plexippus, I see no reason 

 whatever to modify the opinion expressed in my former paper in this 



