Butterfly diagrams for the sub-surface field. Left hand column has C_α < 0, right hand column has C_α > 0. Rows 1–4 have the quasi-solar rotation law, rows 5 and 6 the quasi-cylindrical law. First row: Models 1 and 19 with i_α = 3,m = 4. Second row: Models 6 and 24 with i_α = 1,m = 4. Third row: Models 8 and 26 with i_α = 0,m = 2. Fourth row: Models 12 and 30 with i_α = 1,m = 2. Fifth row: Models 1c and 13c, with i_α = 3,m = 2. Bottom row: Models 7c and 19c, with i_α = 3,m = 4.