Full-grown larvæ were taken on wild cherry (Prunus) in the latter part of September, 1901. Placed in a box over earth, they fed but a day or two, truned a deep green, and entering the earth two to three inches, formed rounded cells, in which they remained as larvæ all winter, transforming to pupæ just before emergence. They are gregarious, remaining in their web, filled with its mass of exuvia, untill full-grown, when, as their growth is completed, individually they drop from it and enter the ground. One which was kept under observation formed a pupa on April 28th, and emerged eight days thereafter. The pupal skin is very thin, showing distictly the parts of the enclosed imago. This brood commenced emerging April 25th, and a few individuals are still coming out, May 31st. In the eariler days the males predominated, later the females, Altogether, 134 males and 123 females have appeared. Copulation took place at once, the pair remaining in coitu from three to five hours.