123 



migrations of another butterfly, Vanessa cardui (Lyell's Princi- 

 ples of Geology, vol. iii, p. 63), but the presence of other 

 insects makes the case distinct and even less intelligible. Be- 

 fore sunset a strong breeze sprung up from the north, and this 

 must have caused tens of thousands of the butterflies and other 

 insects to have perished. 



In the Entomologist (vol. iii, p. 226) it is stated that dur- 

 ing a cyclone, and at a distance of 600 miles from the African 

 coast and 200 from the Cape Verde islands, a vessel was vis- 

 ited by numerous birds and butterflies, the latter being Diadema 

 bolina and Pyrameis cardui. 



Now the instance related by Darwin only proves the fact of 

 flocks of butterflies being observed ten miles from land, and 

 that recorded in the Entomologist leaves it an open question 

 as to whether the insects were direct from the coast of Africa 

 or Cape Verde Is., 1 or indeed whether they occurred in remark- 

 able numbers. We have, therefore, reason to believe that the 

 vast host of Terias lisa which arrived at the Bermudas on the 

 1st of October last, and that visitation recorded in the " Nat- 

 uralist in Bermuda " as occurring on the 10th of October 1847, 

 are the only instances known of such extraordinary flights of 

 Lepidoptera, or indeed any insects being met with at such an 

 amazing distance from land. 



The question, therefore, naturally arises — How did this im- 

 mense concourse of butterflies get to the Bermudas ? The 

 nearest point of land is Cape Hatteras, in North Carolina, which 

 is somewhere about 600 miles distant, and if they had started 

 from this point and taken a straight line to the islands, without 

 meeting with any contrary winds, it would, at the rate of 12 

 miles per hour (a fair average rate of travel for any of the 

 Pieridae), have taken them two days and two hours (of course 

 including nights) to complete the distance; a space of time 

 almost too great, we should imagine, for an insect in no degree 

 remarkable for robust frame or strength of wing to keep up a 

 continuous flight. We are, however, inclined to think that the 

 presence of this vast concourse of insects at the Bermudas was 



i I do not find any record of the. occurrence of P. cardui in the Cape de Verde 

 islands, although it is found on the islands to the north. — S. II. Scudder. 



