Figure 1 from Zwick (2009). Diagrams and photos of the principal male genital sclerites and muscles; red arrow indicates a change in muscle arrangement, either due to a shift of the muscle attachment point (solid arrow) or due to a change in the sclerite it attaches to (dotted arrow); yellow arrow marks the attachment of m2; black arrow marks the proximity of m4 to m5. AV, anterior view; PV, posterior view; see Appendix for figure label abbreviations; scale bars ¼ 0.5 mm. (A) Bombycoidea, PV; gnathos and valvae are widely separated. (B) Anthelidae, PV; gnathos and valvae are fused; mesal fold forms a mesal protrusion. (C) Anthelidae, PV; gnathos and valvae are fused; mesal protrusion and anellus are fused; remainder of mesal fold forms valva apodeme lobe. (D) Bombycoidea, AV (gnathos, subscaphium and anellus omitted); typical configuration of muscles. (E) Same as (D), but with alternative attachments of muscles m2, m3 and m5. (F) Carthaea saturnioides (Carthaeidae), AV; m2 and m4 function as antagonists due to a modified attachment of m4. (G) Endromis versicolora (Endromidae), AV; m2 and m4 function as antagonists due to a modified attachment of m2. (H) Agrius convolvuli (Sphingidae), AV; m2 attaches to the apex of an anteroventral lever of the valva apodeme, ventrally of m4; m2 and m5 are removed in the left half, revealing the lever. (I) Oenosandra boisduvalii (Oenosandridae), AV; attachment of m2 to an antero-ventral lever of the valva apodeme. (J) Agrotis infusa (Noctuidae), AV; attachment of m2 as in (I). (K) Poecilocampa populi (Lasiocampidae), AV; attachment of m4 to the annulus in a dorso-lateral position. (L) Same as (K); m5 attaches directly ventrally of m4. (M) Munychryia senicula (Anthelidae), AV; m5 attaches to the vinculum dorsally of and posteriorly to m4 (‘‘overlapping’’). (N) Anthela euryphrica (Anthelidae), AV; attachment of m5 as in (M). (O) A. virescens (Anthelidae), AV; m5 attaches far ventrally of m4. (P) Crinocraspeda torrida (Lasiocampidae), dorsal view (posterior to the right); fusion between the two dorsally expanded vinculum ends, which are also fused posteriorly to the remnants of the tegumen. (Q) Gastropacha sp. n. (Lasiocampidae), AV; m4 is in a dorsal position on the annulus, filling the entire dome-shaped dorsal part of the enlarged vinculum; note the median gap between the two vinculum halves, which is atypical for a tegumen. (R) Nataxa flavescens (Anthelidae), AV; torsion of muscles m5. (S) Pselaphelia flavivitta (Saturniidae), lateral; well sclerotized gnathos is fused to the valva; gnathos arm might have been misinterpreted as muscle m2 by Birket-Smith (1974).