Aside from the wide distribution of its food plant and possibly correlated with it through the diversity of climatic conditions under which the insect has developed, this butterfly is remarkable for its powers of flight. Many instances are known where it has been taken at sea long distances from land. This is due not only to the propensity of the individual for taking aerial journeys, but also to the fact that this is one of the butterflies which has the instinct to congregate in swarms and to migrate long distances when thus congregated. In 1879 such a flock started from Africa and migrated to Europe. One of the most remarkable things about this butterfly is our ignorance of what it does with itself in winter. American entomologists are agreed that the adult butterfly hibernates, but where it does so seems not to be known. Here is an excellent opportunity for some young naturalist to go scouting, hunting in board piles, under loose bark, or with a flashlight searching the interiors of hollow trees to find between November and April living specimens of this butterfly. Such a discovery would be a real service to science and should at once be made known through some scientific journal. In Europe there seems to be a belief that the insect hibernates partially at least in the condition of the chrysalis. _The Life-story_ While we may not know just where the butterflies have been throughout the winter, we do know that in southern New England they begin to be seen in fields and along roadsides about the middle of May. Many of the specimens then have a ragged appearance which is a pretty good indication that they came from the chrysalis the fall before and have been lying concealed through all the weeks since. These butterflies lay their small greenish, barrel-shaped eggs on the leaves of the thistle. The mother butterfly chooses the location rather carefully and deposits only one egg upon a leaf. The butterflies continue thus to visit flowers and to lay eggs until about the middle of June when apparently they perish. About a week after the egg has thus been laid, it hatches into a small spiny caterpillar which does not take the trouble to devour its egg shell as so many other caterpillars do. Instead it crawls around to the lower side of the leaf and gnaws off enough of the silken surface of the leaf to furnish material for making a webby covering, the leaf particles being woven together by threads from the caterpillar's mouth. In this way the little creature soon provides itself with a snug enclosure which serves it as a temporary home. It remains in this home much of the time when not eating, going out occasionally to feed upon the green tissues of the adjacent parts of the leaf.