In some years the "tent caterpillar" of this moth occurs in enormous abundance, with huge communal nests on almost every branch of almost every broad-leaved tree. (Maples seem to escape.) The numbers fluctuate from year to year, but it was strange that in 2000 and again in 2001 the species was quite scarce and apparently completely absent from some areas. It will be interesting to see whether the populations build up again. The cocoon is a double-walled structure covered with a yellow powder. Moths emerge in July and August. The photographs show a male (with feathery antennae) and a female (with thread-like antennae).