Eruciform

Eruciform (literally: "caterpillar-shaped") is the entomological term describing a certain class of shapes of insect larvae.

[2] Some larvae, such as those of most beetles in the family Chrysomelidae, are described as eruciform, although they are short, have swollen abdomens, and have no true "prolegs" such as caterpillars have.

Typically they walk freely on leaves and similar surfaces, using the "true" six legs on the three thoracic segments just behind the head.

In contrast, larvae of the Cerambycidae (Longhorn beetles) are generally straight and could fairly be described as "apodous eruciform".

They live in tunnels, typically in wood, where a distended abdomen would be a liability and legs are not the only option for locomotion.