Mike Dale says: In solandriana the sterigma are wider and flat topped compared to brunnichana which are narrow, elliptical with usually a small indentation on the apex.
The signa in solandriana are both placed towards the bottom of the corpus bursa and orientated horizontally, whereas in brunnichana there is one much higher in the corpus bursa and both are orientated at a 45 degree angle approx. Razowski* (plate 68) appears to indicate this, but Nel** (planche 98) does not, and the feature should be used with caution.
*Tortricidae of Europe
František Slamka 2003
**Atlas des Genitalia femelles des Lépidoptères Tortricidae de France