In Butterflies of N. A., Vol. 2, Part 8, 1879, I gave the history of Arthemis, and stated that it was single-brooded ; that the first butterflies of the season appear in the Catskills about the end of June; that they are abundant during July; that the eggs are laid last of July and early in August; that the larvæ from these eggs pass two moults and then go into lethargy in cases of their own construction ; that they come from these cases in spring and moult twice before chrysalis.