I found a young caterpillar in July on willow. At first it looked
like a typical green and hairless "cutworm" type of noctuid caterpillar,
but is eventually grew to an astonishing size, comparable to the caterpillar
of Smerinthus cerisyi. The moth emerged in
late August and was quite fearsome in appearance. The dorsal surface of the
thorax bears an unusual rather hard brown shield-shaped plate. Moths of this
genus are known as swordgrass moths. They spend the winter as adult moths.