84 



that this butterfly could have traversed two thousand miles of 

 ocean, and in addition have appeared on an island less than 

 twenty miles in diameter almost simultaneously with a few 

 plants of Asclepias, accidentally introduced ! The only other 

 alternative is to suppose that it was carried to the island with 

 the box of plants sent to Dr. Gulick. But the precise manner 

 of its introduction is still a perplexing question. In a vast ma- 

 jority of cases the accidental transportation of insects from one 

 country to another is during their preparatory stages ; but in 

 this case the voyage is known to have taken nearly eight weeks, 

 while the transformations of the Danaida, even in a temperate 

 country, seldom occupy more than four or five weeks, and in 

 the tropics doubtless take less time. So that, should a plant 

 of the Asclepias weed, bearing eggs of the Danaida just laid, 

 have been accidentally introduced into the Wardian case sent 

 to Dr. Gulick, the butterflies would certainly have appeared in 

 the closed case before the voyage was half over ; and we must 

 suppose that the caterpillars from which they were produced 

 had eaten up every trace of Asclepias, that the butterflies 

 themselves remained therein unseen for a month, and that at 

 least a pair of them made their escape unnoticed from the case 

 on its arrival at Ponape. 



This seems quite impossible. And although Dr. Gulick dis- 

 tinctly says that the " diminutive hold and cabin " of the vessel 

 "were several times ransacked in every corner before it reached 

 our island, so that no such butterfly as the Danaus could 

 easily have - been concealed there," this seems to be the only 

 other alternative, and one which the long duration of this 

 stage of the insect and its power of extended hibernation 

 directly favor. In this case we must suppose that a pregnant 

 female flew into the hold (to rest for the night) while the ves- 

 sel was loading at Honolulu and, undergoing a forced imprison- 

 ment (or pseudo- hibernation) during the voyage, escaped on 

 unlading and in course of time found Asclepias ready for its 

 necessities. A single butterfly, even of the great size of Dan- 

 aida Plexippus would easily escape observation flying at large 

 about a wooded tropical island. Samuel H. Scudder. 



