Geranium leaves

Geranium leaves

Observation - Geranium leaves. Description: Can anyone suggest which invertebrate might have made the sausage-shaped holes in these cultivated Geranium sp. leaves? We have many similar Geraniums in the garden, but only this one has leaves fretted in this very distinctive way.

Can anyone suggest which invertebrate might have made the sausage-shaped holes in these cultivated Geranium sp. leaves? We have many similar Geraniums in the garden, but only this one has leaves fretted in this very distinctive way.