_Butterfly._--The male on the upper side is pale yellow, with a greenish tinge on the hind wings; the black borders are narrow; the fringes are pink. The female on the upper side is white, with very little or no black on the outer borders, the black marking being confined to the apex of the fore wings. On the under side the wings are much as in _C. interior_, and it is possible that the two forms are varieties of one and the same species. Expanse, 1.60-1.85 inch. _Early Stages._--Little is known of these. _Pelidne_ is rather abundant in Labrador at the proper season, and ranges thence westward and northward in boreal America. (10) =Colias nastes=, Boisduval, Plate XXXVI, Fig. 11, ♂; Fig. 12, ♀ (The Arctic Sulphur). _Butterfly._--Easily recognized in both sexes by the pale-greenish tint of the wings and the tendency of the outer border of the fore wings of the male to become divided, like those of the female, by a band of pale spots. Expanse, 1.50-1.65 inch. _Early Stages._--Unknown. This is an arctic species, which is found in Labrador, Greenland, the far North in British America and Alaska, and on the summits of the Rocky Mountains in British Columbia. (11) =Colias behri=, Edwards, Plate XXXVI, Fig. 17, ♂ (Behr's Sulphur). _Butterfly._--This very rare little species may be easily recognized by the dark-greenish tint of the upper side of the wings and the light spot on the upper side of the hind wings. The female has the outer borders dusky like the male, the dusky shade running inward on the lines of the veins and nervules. Expanse, 1.50 inch. _Early Stages._--We know little of these. The insect has hitherto been taken only at considerable elevations among the Western Sierras, and the peaks and lofty meadows about the Yosemite Valley have been until recently the classic locality for the species. There are a number of other species of the genus _Colias_, and numerous varieties which have been named and described from the western and northwestern portions of our region; but it requires almost as much skill to distinguish them as is required to discriminate between the different species of willows, asters, and goldenrods, among plants, and we do not think it worth while to burden the student with an account of these, and of the controversies which are being waged about them. If any reader of this book becomes entangled in perplexities concerning the species of _Colias_, the writer will be glad to try to aid him to correct conclusions by personal conference or correspondence. Genus TERIAS, Swainson (The Small Sulphurs) "Hurt no living thing: Ladybird, nor butterfly, Nor moth with dusty wing, Nor cricket chirping cheerily, Nor grasshopper so light of leap, Nor dancing gnat, nor beetle fat, Nor harmless worms that creep." CHRISTINA ROSSETTI.