MIGRATION AND DISPERSAL OP INSECTS : LEPIDOPTERA. 319 



here, in the village of Paul ; I saw another in the museum garden 

 flying over a plant of fuchsia, but unfortunately for the museum col- 

 lection I did not net it. Vines grow on the walls here, but I have not 

 yet obtained larvie. For speed this insect is hard to beat, J question 

 if aV. cdurolndi can travel so fast. MacnKjIossa stdlataritni, flying in 

 greater numbers in 1H99 than I have ever seen in previous years. If 

 I had wished I could have taken hundreds at fuchsia flowers ; the best 

 time to capture them was from 8 a.m. -10. 30 a.m., and again from 

 5 p.m. till dusk ; fewer were observed flying in the middle of the day. 



Migration and Dispersal of Insects: Lepidoptera. 



By J. W. TUTT, F.E.S. 



The migration of butterflies and moths is more especially interest- 

 ing because the raiaon d'etre that exists for migration in locusts, and, 

 to a less extent, in dragonflies, is absent in these insects, for, in their 

 winged state, they have no voracious appetite to satisfy that can pos- 

 sibly act as a stimulus to them to leave their native haunts. 



It is probable that, in recent .years at least, more attention has 

 been paid to the lepidoptera than to any other order of insects. 

 Those entomologists who make the lepidoptera their special study, far 

 outnumber those who devote their attention to all the other orders of 

 insects combined. Scarcely a county in Britain but has a bevy of 

 careful and intelligent observers, so that the absence of an usually 

 common species, or the influx in unusual numbers of a rare one, is at 

 once recorded. It is not surprising, therefore, that there are many 

 notes relating to the migration of these insects. 



Probably one of the oldest references made to migrating butterflies 

 is that of Moufl'et who writes : " Wert thou as strong as Milo or 

 Hercules and wert fenced or guarded about with a host of giants for 

 force and valour, remember that such an army was put to the worst 

 by an army of butterflies, flying in troops in the air, in the year 1104, 

 and they hid the light of the sun like a cloud." 



It is generally supposed that after the Glacial Epoch had given 

 place to more temperate conditions, there was a gradual movement of 

 living creatures from the south and east, northward. Butterflies and 

 moths, the ancestors of those now in existence, doubtless shared in 

 this movement, following slowly but surely the retreat of the ice, some 

 at a nearer, some at a greater, distance, and, in a measure, even now, 

 similar movements of certain species appear to be still going on. The 

 occasional appearance of Colias cdtma, C. In/air and ruraincis cardiii 

 (whose true home is in the warm Mediterranean region of southern 

 Europe and northern Africa) in immense numbers, at more or less 

 irregular periods and in comparatively high northern latitudes, points 

 to northward movements of great magnitude, and to an attempt on 

 the part of these butterflies to establish themselves in lands far 

 removed from their native haunts, 



A peculiar feature in the migration of lepidoptera is the large 

 number of comparatively weak-winged species that have been observed 

 at immense distances from land. That these flights are usually quite 

 voluntary, and not due to wind-storms, is shown by the fact that many 

 observers (among others Darwin) have noticed that the flights have 

 commenced in calm and still weather. 



