Found eating my hollyhock leaves

the caterpillar of the Vapourer Moth, Orgyia antiqua, feeds on a wide range of plants. The male adults are very active and often fly by day; the females do not have wings and are essentially big bags of eggs with a special smell that draws the MALES to them!   So I am wondering how they have reached my 5th storey high flat in the center of the city! A great looking beastie though  but not when they are decimating my leaves.  However, there only seemed to be two so amongst 8 plants I hope they will gorge on enough and pupupate soon