Some of the more interesting phases in the development of these insects are discussed in connection with the life-stories of the different species. A phase which is characteristic to all of them may well be emphasized here. From the time the caterpillars hatch until they change to chrysalids they illustrate to a marked degree an adaptation through structure and habit which must very largely protect them from attack by birds and other enemies. Their structure and markings are almost grotesque. The body is covered with strange club-like appendages and it is colored with a curious mottling of tones of green, drab, brown, and white which is very difficult to describe but which suggests, as the caterpillar rests upon rough bark, simply a bit of bird dung or some natural excrescence. The caterpillars have the habit of feeding at night and remaining upon their perches by day, often assuming positions which are very unusual among insect larvae. Such positions, in which they remain motionless for hours at a time, are undoubtedly of protective value and help to conceal the insect. After the caterpillars are half grown they rest not upon the leaves upon which they feed, but rather upon the bark of twigs or branches where their peculiar structure is likely to make them inconspicuous. The chrysalids of the Sovereigns are also curiously mottled in color tones that will probably lead to their being overlooked. Three distinct species of Sovereigns are found in eastern North America, namely: The Viceroy, _Basilarchia archippus_. The Banded Purple, _Basilarchia arthemis_. The Red-spotted Purple, _Basilarchia astyanax_. The first species, the Viceroy, has a much wider distribution than either of the others. It apparently is found in nearly all localities in which either of these occur, and so includes within its range almost the whole of the United States and much of Canada. The second of these, the Banded Purple, is a northern form. It is found commonly at least as far north as the Mackenzie River region in British America and southward to central Massachusetts. It also occurs as far west as Nebraska so that it has a very wide distribution in northern regions. It is especially abundant in Canada and the White Mountains. The third, the Red-spotted Purple, is the characteristic form south of latitude 42 degrees. Its range overlaps that of the Banded Purple for about one degree but it is seldom found north of latitude 42 degrees. It seems to range about as far west as the Banded Purple.