Moth Week 3: Inch worms

Nematocampa resistaria the Bordered Thorn

The caterpillars of moths in the family Geometridae (earth measurers) are often called inch worms or span worms or measuring worms or loopers from their peculiar way of walking.

Erannis tilaria the Linden Looper measuring a leaf

Legs at either end of the body alternately grip and relax as the body is drawn towards the attached end.

Linden Looper looped up

But the larva of the Bordered Thorn Nematocampa resistaria (Herrich-Schäffer, 1856) is called the Filament Bearer because of the strange, thorn-like processes that can be everted from its back, trump its looping habits.

Pale Beauty form of the Fringed Looper

Although their larvae are sometimes pests, e.g. the Linden Looper can cause significant defoliation, geometrids are always interesting and sometimes quite beautiful, as in the ghostly green Pale Beauty Campaea perlata Guenée, 1858