Moths of the genus Hydriomena are
popularly referred to as "highflyers", though I'm not certain that they fly
particularly higher than other moths. To my eye, H. manzanita doesn't
look quite like a typical highflyer. Someone once asked me how to tell the difference
between a geometrid and a noctuid, and I replied that geometrids rest in "landscape"
mode, while noctuids rest in "portrait". Hydriomena manzanita doesn't
obey this rule, for it is decidedly "portrait" and could be mistaken for a noctuid.
The caterpillar can be found between two leaves of Madrone (Arbutus menziesii) in May. Presumably from its name it also feeds on the related Manzanita (Arctostaphylos sp.). In late June it stops feeding and hides between the two leaves in larval diapause for several months, forming a pupa sometime in early winter. The moth emerges in May.