Who's eating my plants?

Who's eating my plants?

Observation - Who's eating my plants?. Description: Found two of those in my front garden this evening, no idea what they are. As you can see in the photo, they have managed to completely denude the Silene maritima they are sitting on, so I hope at least they will morph into something beautiful! Any help w

Found two of those in my front garden this evening, no idea what they are. As you can see in the photo, they have managed to completely denude the Silene maritima they are sitting on, so I hope at least they will morph into something beautiful! Any help with ID will be greatly appreciated!