Three branches arising from the radius of each front wing. Under surface of hind wing commonly marked with threadlike streaks: the Hair-streaks.
Four branches arising from the radius of each front wing. Under surface of hind wing commonly marked with spots rather than lines.
Colors brownish red: The Coppers.
Colors blue: The Blues.
The Hair-streaks are small butterflies with the eyes notched to allow for the insertion of the bases of the antennae. The name is given on account of the fine, hair-like markings which extend across the under surface of the hind wings. In many species there is a tailed projection or two on the hind inner margin of the hind wing. The caterpillars are remarkable for the small head, so connected with the body that it can be pushed forward in a characteristic way.
The Hair-streaks are among the most exquisite and delicate of all our butterflies. A large proportion of them have the upper surface of the wings toned in beautiful hues of grayish brown and the under surface lighter gray, marked with dots and stripes, some of which are brilliant in coloring. A few of the larger species are brilliantly iridescent in purples, blues, and greens, marked with black. The males have well-developed scent-pockets in many species, these being commonly along the front border of the front wing.
A very interesting suggestion in regard to the possible function of the curious tail projections was made nearly a hundred years ago by some English entomologists and has since been discussed at considerable length in various publications. It is that the slender tails, together with the enlargement of the wing just back of them, give the impression of a false head. Along with this unusual development of the wing is to be considered the fact that these butterflies nearly always alight head downward so that the false head, furnished with what seem to be waving antennae, takes the place that would naturally be occupied by the true head. Instances have been reported in which this false head has apparently been nipped off by a lizard and much evidence has accumulated to indicate that this curious device may be a real protection in many cases. Of course, the loss of the tails and the part of the wings adjacent would be comparatively insignificant. In most cases, these projections on the wings are held at right angles to the plane of the wing.
While nearly half a hundred species of Hair-streaks have been found in North America, only a few of these are sufficiently abundant to require discussion in this little book.