Pictures of larvae of the two studied Hemichroa species. a, b H. australis, solitary (body length ca. 18 mm) c, d H. crocea, gregarious (body length ca. 20 mm). Field host-plant [sawfly collection reference number]: a Alnus glutinosa [P2553] b A. glutinosa [P3999] c Betula verrucosa [P3225] d A. glutinosa [P3230]