_Butterfly._--Quite small; the male pale blue above, edged with dusky; the female dusky, with the inner two thirds shot with blue. The maculation of the under side is as represented in the plate. Expanse, .80 inch. _Early Stages._--Unknown. Habitat, southern California. (16) =Lycæna sonorensis=, Felder, Plate XXXI, Fig. 21, ♂; Fig. 22, ♀ (The Sonora Blue). _Butterfly._--Easily distinguished from all other species of the genus by the red spots in the region of the median nervules on the upper side. Expanse, .87 inch. _Early Stages._--Unknown. This lovely little insect is found rather abundantly in southern California and northern Mexico. (17) =Lycæna podarce=, Felder, Plate XXXII, Fig. 15, ♂; Fig. 16, ♀ (The Gray Blue). _Butterfly._--The male is grayish-blue above, with dusky margins, lighter on the disk of both the fore and hind wings. There are a few dark marginal crescents on the hind wings. On the under side the wings are very pale, profusely spotted, the spot at the end of the cell of the secondaries being large and whitish, without a pupil, the rest being black ringed about with white. The female is dark brown above, the fore wings having a black spot ringed about with yellowish at the end of the cell. Expanse, 1.05 inch. _Early Stages._--These have never been described. The species is thus far known from California, Nevada, and Colorado. It is alpine in its habits. (18) =Lycæna aquilo=, Boisduval, Plate XXXII, Fig. 9, ♂; Fig. 10, ♂, _under side_ (The Labrador Blue). _Butterfly._--The male is dusky bluish-gray on the upper side; the female somewhat darker. It is easily distinguished from other species by the dark-brown shades on the under side of the secondaries. Expanse, .80 inch. _Early Stages._--Unknown. It is found in Labrador and arctic America. (19) =Lycæna rustica=, Edwards, Plate XXXII, Fig. 17, ♂, _under side_ (The Rustic Blue). _Butterfly._--Much like the preceding species, but a third larger, and brighter blue on the upper side of the wings of the male. On the under side the disposition of the spots and markings is precisely as in _L. aquilo_, but on the secondaries the dark spots and shades are all replaced by white on a pale-gray ground. Expanse, .90-1.00 inch. _Early Stages._--We are in complete ignorance as to these. The butterfly is found in British America and on the Western Cordilleras. (20) =Lycæna enoptes=, Boisduval, Plate XXX, Fig. 30, ♀, _under side_; Fig. 51, ♂ (The Dotted Blue).