Abstract
THE observations of D. and E. Lack1 on a southerly migration of insects in October 1950 at Port de Gavarnie in the Pyrenees, which has since been confirmed in October 1951 by Messrs. D. W. Snow and K. F. A. Ross2 and others, makes possible a hypothetical interpretation of migration on a genetic basis for the first time. They observed between a hundred and five hundred butterflies per hour (Colias croceus, Vanessa atalanta and Pontia daplidice), one thousand to five thousand dragonflies (Sympetrium striolatium striolatium), and the syrphid fly (Episryphus balteatus), “at least twenty times and perhaps one hundred times as common as the dragonflies” flying in a southerly direction. Dr. C. B. Williams3 has for many years shown a southerly migration in Vanessa atalanta and more recently in C. croceus in Great Britain in the autumn, and the southerly migration of D. plexippus is a well-known fact in North America.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
