Abdomen
The abdomen is generally considered to be based on 10 segments. In males segments A1-8 have an integument and the genitalia are derived from segments A9&10. In females segments A1-7 have an integument and the genitalia are derived from segments A8-10. The dorsal plate of A1 is modified for articulation with the metathorax. The dorsal plates of segments A1-6 (and sometimes A7) have paired patches of short thorny spines, which are exposed in nearly all species, (but covered by scales in C.lutarea and A.aeratella)*. The ventral plate of A1 is obsolete (as in all Ditrysia) and A2 is elongate, laying opposite dorsal plates A1&2. The ventral plates of A3-6 are usually well-sclerotised and transverse.
In males the ventral plate of A7 is usually more narrowly sclerotised than A3-6 and A8 is only sclerotised in a narrow line at its anterior margin.
In females the ventral plates are all broader than in the male and A7 is much longer than A3-6 on both surfaces.
In males the ventral plate of A7 is usually more narrowly sclerotised than A3-6 and A8 is only sclerotised in a narrow line at its anterior margin.
In females the ventral plates are all broader than in the male and A7 is much longer than A3-6 on both surfaces.
*MBGBI3 states that the dorsal abdominal spiny patches are also covered by scales in C.limoniella - but this is incorrect.