It has generally been supposed that this species is double-brooded in central and southern New England, the butterflies of the first brood appearing early in July. These are said to deposit eggs which hatch into caterpillars that mature into butterflies early in September. These butterflies live through the winter, laying eggs the following spring. It is very probable that as far north as southern New Hampshire the species is commonly single-brooded. During one season when the caterpillars were unusually abundant, a very careful watch was kept for the second brood in New Hampshire and Vermont by several competent observers. Only one colony of caterpillars was found and this was at Durham in the southern part of New Hampshire near the seacoast. Consequently, it seems safe to conclude that in northern and central New England, at least, a single brood is the rule rather than the exception. This involves the conclusion that the butterflies seen upon the wing early in autumn are the same ones that developed in July, and that these same butterflies remain alive through the winter and until, in the following May, they lay their eggs. Thus there is a period of ten months of existence in the butterfly state, an extraordinary length of time for a butterfly to live. To a large extent the butterflies disappear in August, and the question arises as to what becomes of them. Our observations lead to the conclusion that they go into summer quarters similar to those which they seek out for winter shelter. Apparently they fly about for a few days after coming from the chrysalis and then retire to cool woods, where under the side of a log or beneath the loose bark of a dead tree they settle down and to all appearances go to sleep. The instinct to remain quiet is very strong in these butterflies. In taking the accompanying photographs, I found that even shortly after coming from the chrysalis the butterflies when disturbed would fold their wings with the antennae between them, and drawing the legs against the body would lie quietly on their sides for a long time. These same butterflies would also hang downward from a limb by the hour in the hibernating position as shown in plate opposite page 32. In the cooler weather of early autumn, the butterflies come from their retreats and fly about in the sunshine. They are especially likely to be seen along the borders of woods or in open glades. At this time they love the sunshine, and will settle in a sunny place to bask in it. _Going into Winter Quarters_ When the warm days no longer tempt them abroad, the Mourning-cloaks seek shelter in many sorts of situations--under loose bark, in hollow trees, under culverts and bridges, in woodpiles, in crevices of rocks, or alongside logs lying on the ground. In such retreats they remain until the sunshine of spring again calls them forth.