When autumn comes our caterpillar is faced with the problem of passing through the winter successfully. It must shelter itself from birds, spiders, predaceous beetles, and many other enemies. It must find a means of keeping out of the reach of snow and rain, for while it can survive a great degree of cold as long as it keeps dry, it might easily be killed by freezing up with moisture. But the caterpillar is able to provide against these dangers. It has apparently an abundant supply of liquid silk to secrete from the silk glands in its head, so it lines its tubular tent with a dense silken web that effectually excludes enemies and moisture. It thus has on the outside of its nest the thick oak leaf and on the inside a dense soft lining that makes a most admirable winter protection. So it remains here throughout the winter, the leaf commonly staying on the tree until early spring. Then leaf, nest, and enclosed caterpillar are likely to drop to the ground to remain until spring arrives in earnest. Just what happens then seems to be a bit doubtful. The caterpillar changes to a chrysalis, but whether it first works its way out of its winter nest and makes a new and less dense covering seems not to be certainly known. Here is another good opportunity for some careful observations. At any rate, the caterpillar changes to a chrysalis, and late in spring it changes again to an adult butterfly that flits about on dusky wing for a few weeks before it dies. =The Sleepy Dusky-wing= _Thanaos brizo_ The appearance of this butterfly both as to size and marking is very similar to that of Juvenal's Dusky-wing except that the white spots are not present on the front wing of this species. The life-histories of the two species as well as their distribution seem to be closely parallel. The present butterflies are to be found early in summer in the same oak barrens as the other, the blueberry blossoms being freely visited for nectar by both species. =Persius's Dusky-wing= _Thanaos persius_ This is a rather small, dark brown Skipper, with a few white spots toward the apex of the front wing, but otherwise not marked except for a very pale transverse band which is almost obsolete. The butterfly is found from ocean to ocean along the northern tier of states. It also occurs in the Eastern states as far south as Florida as well as in the states along the Pacific Coast.