Mystery of Migration Doubtless most of the public comment on
butterflies has had to do with the wholly unexplained mystery of migration, which, in regard to insects as opposed to birds, seems to be nature's method of destruction rather than preservation, for the immigrants, at least to England, are wont to perish utterly in some species. What is perhaps more surprising than the immigration, say, of white butterflies, which are very strong fliers, is the immigration of moths, whose arrival on our shores in very large numbers seems to pass quite unrecorded, except in a specialistic journal. Once, and once only, have I actually seen a moth arrive from over the sea, and that was in May on the coast of Devon, when a bevy of Humming Bird Hawk Moths hovered about the rocks in company with a larger host of Painted Ladies. At the very same place battalions of swallows were watched about this date making several trial flights out to sea before they left for good. They seemed reluctant to depart till the weather worsened. In general one sees little of the actual process even of bird migration.