In Southern states, the females begin laying eggs in late April, in Northern states they begin egg laying in late spring/ early summer. The fecal droppings from both the adults and larvae can leave spotted stains on your car’s exterior.
It is the adults of the last generation which normally enter structures for the winter. They may find shelter under siding, in walls, ceiling voids, attics, chimneys, behind curtains, drapes, under carpets, between books, and in other safe and warm environments. Inside they are a nuisance pest. Their droppings will leave stains from their droppings or if crushed.