Caterpillar:
Noun. Pronunciation: /ˈkatəpɪlə/
1. The larva of a butterfly or moth, which has a segmented body resembling a worm with three pairs of true legs and several pairs of leg-like appendages.
1.1. (In general use) any insect larva resembling the larvae of caterpillars and moths, especially that of the sawfly. (Oxford Dictionary)

Here are some examples I’ve spotted of these insect larvae.

These black-and-yellow striped critters are Cinnabar moth caterpillars (Tyria jacobaeae), chewing away on their favourite food plant, ragwort.

The caterpillars of the Parsnip moth (Depressaria pastinacella) build themselves little silken webs within the structure of the umbellifer flowers (in particular Wild parsnip), on which they feed.

A snapshot of a few others I’ve sighted (from left to right): Drinker moth (Philudoria potatoria), Old lady moth (Momo maura), Vapourer moth (Orgyia antiqua), sawfly larva (possibly of the Large rose sawfly, Arge pagana), Ruby tiger moth (Phragmatobia fuliginosa), and, lastly, the wild extravagance of the Pale tussock moth caterpillar (Calliteara pudibunda).