Note, in P&M Genitalia of the British Tortricidae plate 31 the two males of these species do seem different (see the aedeagus), which I think is an error. In the text mention is given to the two species/forms from the Vine collection, and under "Pammene? nimbana" (=herrichiana) it says "in the absence of reliable material we express no opinion as to whether it is a good species or not"
I think it is only us British who treat herrichiana as a separate species from fasciana as European literature do not cover it. In BTS herrichiana is treated as a form of fasciana but in later literature, The Checklist of Lepidoptera 2nd Revised Edition (Bradley) they are given the numbers 1236 and 1236a. Mapmate also distinguishes the two.
The only way to tell them apart seems to be by rearing through larvae taken form the given food plant. Patocka (Lepidoptera Pupae) gives no mention of distinguishing features in the pupal stage and we are unsure if there are larval differences.
P. herrichiana can sometimes appear greyer in the forewing. We would welcome any further comments on these two species.
