Last summer I was so fortunate as to obtain fifty eggs of the rare Sphinx, Darapsa versicolor. They were found between June 26th and July 20th, on the under side of the leaves of the common swamp button bush, Cephalanthus occidentalis Linn., and, with two exceptions, were laid singly. The egg is round and slightly flattened-about the size of rape seed. It is at first light green and translucent, afterwards milky and opaque; a few before hatching became, about the spot where the larva emerged, russety. The longest any egg continued without hatching was six days, and it is almost a certainty that the duration of the egg state is seven days.