The hemispherical eggs are laid singly or
in pairs on the underside of poplar leaves, and are of an unusual and strangely
conspicuous creamy white colour. Even in the first instar the caterpillar shows
the notodontid habit of raising it last few segments up in the air. The full
grown caterpillar has green, brown or grey colour varieties, and it is remarkable
for at least two things. It is very shiny, looking as though it were covered
with varnish. And it has a "horn" at the end quite similar to the
caterpillars of hawk moths (Sphingidae).