Itiscci MujnUlons in Tropical America. 157 



factors ill causiiii> this migration from the Gulf Region 

 northwards, since the summer of 19UG was still warmer, 

 but witli much greater humidity, and under these conditions 

 only oue pupa was found durhig that entire year." 



In 1911 there was another invasion, which reached as 

 far as Long Island, of which the following particulars were 

 kindly given to me by Mr. F. E. Watson of the American 

 Museum of Natural History. He tells me that two speci- 

 mens, one battered and one in fair condition, were captured 

 during May 1911, one on Long Island and one in Prospect 

 Park, New York City. During August all the cannas in 

 the parks in this district were eaten up by thousands of 

 larvae, from which pupae were obtained which gave 

 indoors, adults in October and November, but out of doors 

 no adults were seen either that autumn or the followhig 

 year. 



There can be no doubt that these sudden extensions of 

 range were brought about by some form of migratory 

 flight. 



Ill Trinidad and the West Indies the butterfly is generally 

 abundant, sometimes sufficiently so as to rank as a pest 

 of canna and arrowroot, particularly in 8t. Vincent. 



During three years' residence in Trinidad I have never 

 seen any migratory movement of this butterfly or any 

 flight in any way resembling that seen in Panama. On 

 the other hand, the sudden appearance of the insect in 

 large numbers in some of the smaller islands, indicates 

 very strongly that these migratory movements take place 

 here also, "in the West Indian Bulletin, vol. 3, 1902, p. 234, 

 Calpodes etJdius is mentioned in an article on insect 

 epidemics as an example of an insect which is liable to 

 very sudden increase in numbers, only later to decrease 

 equally suddenly. No suggestion is however made that 

 the outbreak might be due to migration. 



There was a severe outbreak of the pest in St. Vincent 

 in 1900 and agahi in September 1901, the latter being the 

 occasion of a short investigation by H. M. Lefroy, then 

 entomologist to the Imperial Department of Agriculture 

 for the West Indies. 



In "Indian Insect Life," p. 421, Lefroy says: "From 

 time to time one reads in newspapers of a swarm of butter- 

 flies having been seen flying steadily in a particular direc- 

 tion. We have seen this hi the case of the West Indian 

 skipper {Calpodes etJdius) which was extremely abundant." 



