96 Mr. W. L. Distant's Geographical Dhiribution 



being fed on some weak sugar and water, and Mr. Mitcliell 

 thinks she might have Kved longer, but that in the mean- 

 time he had filled up his case with plants, and as she 

 persisted in keeping near the glass, her Avings were con- 

 tinuously drenched by the moisture collected on it.* This 

 butterfly also hybernates, though Mr. Kiley remarks whe- 

 ther any but the impregnated females survive until the 

 milk weeds commence to grow is not definitely ascer- 

 tained. 



In the Atlantic Ocean, to the north of the parallel of 

 35°, there is a very decided prevalence of winds from the 

 westward. In the southern and south-western position 

 of this broad region they blow almost continuously from 

 S. W., or veering from that to W. ; and are often found 

 much further south, near the American coast, during the 

 summer months, when southerly and south-westerly winds 

 are common to the coasts of Florida and Georgia. f The 

 most furious gales of wind frequently blow across this 

 region in the same direction. Even gales that take their 

 rise on the coast of Afi-ica, and as far down on that side 

 as the parallels of 10" or 15° N. lat., have, it has been 

 shown by an examination of log-books, made straight for 

 the Gulf Stream : joining it, they have then been known to 

 turn about, and, travelling with it, to reach the shores of 

 Europe. I Mr. Packard, jun., has lately drawn attention 

 to the agency of the average direction of the winds in 

 influencing " the migi-ation of the destructive locust of 

 the west." § Prof. Baird, in his memoir on the distribution 

 and migration of North American birds, has shown a 

 strong analogy to what might have occurred in the case 

 of D. Archippus. Most specimens of American birds 

 recorded as found in Europe were taken in England 

 (about fifby out of sixty-nine), and in nearly all cases 

 these specimens belonged to species abundant during 

 summer in New England and the Eastern provinces of 

 British America, and in the great majority of instances 

 their occurrence here has been in the autumnal months. 

 Prof. Baird therefore concludes that the transfer of Ame- 

 rican birds to Europe is principally, if not entirely, by 



• Am. Nat. vol. vi. p. 237. 



\ This subject has been most exhaustively treated in detail by the late 

 J. H. Coffin, and completed by his son S. J. Coffin and Dr. Woeikof, in 

 Smith. Trans, vol. xx. 



X Maury, Phys. Geo. of Sea, p. 33. 



§ Am. Nat. vol. xi. p. 22. 



