49.310 Dichrorampha sedatana (Tansy Moth)
ws: 12-16mm; May-Jul; tansy (Tanacetum vulgare); NS-B throughout GB
Dichrorampha sedatana §1 male
ID: Median dorsal blotch obscured, ground colour brown. Requires genital determination. D.plumbana/sedatana/aeratana are very similar. D.sedetana/aeratana average larger (ws 12-16mm) than D.plumbana such that specimens with fw 7mm or more should not be D.plumbana. D.sedatana has the pale yellow irroration extending to the base of the wing whereas in D.plumbana/aeratana the basal third is largely devoid of yellow colour.
Male genitalia: Juxta lobes triangular and weakly scobinate; aedeagus with subapical teeth.
Female genitalia: Sclerotised antrum simple and extends to ½ length of A7; posterior ostial margin with a midline hump > D.plumbana/sedatana
As far as I have been able to discern these two are indistinguishable on female genital features.
See Dichrorampha for more information.
D.plumbana/sedatana/aeratana have well-developed juxta lobes and this readily distinguishes them from all other Dichrorampha species. In the past this distinction has been sufficient to place these three species in a separate genus.
The male genitalia are illustrated and described by P&M (unreliable*), BTM (not very reliable), MBGBI5.2 (useless), Sterling and Parsons (more helpful in 1st edition, not illustrated in 2nd edition) and are shown at Moth Dissection (reliable).
1. Aedeagus: D.plumbana - tapered without teeth; D.sedatana - 2 tiny dorsal subapical teeth; D.aeratana - 1 tiny dorsal subapical tooth
2. Juxta lobes: D.plumbana/sedatana - triangular and very weakly scobinate; D.aeratana - rounded and strongly scobinate
3. Emargination of ventral margin of valva: D.plumbana/sedatana - narrow; D.aeratana - broad
BTM also emphasises that D.plumbana has a narrower cucullus than in D.sedatana/aeratana and S&P mention that the cucullus is slightly smaller in D.plumbana. The images at Moth Dissection suggest that this difference is sufficiently indistinct that it would be unreliable - it is certainly not nearly as apparent as the illustrations in BTM (p304) would suggest.
(P&M differentiate a further species L.torrana and confusion reigns in any further attempt to differentiate the species from this source: P&Ms male L.torrana is D.plumbana, their female L.aeratana is D.plumbana, their female L.torrana is D.aeratana and their female L,plumbana is D.aeratana - which leaves their male L.plumbana as unmatched).
Male genitalia: Juxta lobes triangular and weakly scobinate; aedeagus with subapical teeth.
Female genitalia: Sclerotised antrum simple and extends to ½ length of A7; posterior ostial margin with a midline hump > D.plumbana/sedatana
As far as I have been able to discern these two are indistinguishable on female genital features.
See Dichrorampha for more information.
D.plumbana/sedatana/aeratana have well-developed juxta lobes and this readily distinguishes them from all other Dichrorampha species. In the past this distinction has been sufficient to place these three species in a separate genus.
The male genitalia are illustrated and described by P&M (unreliable*), BTM (not very reliable), MBGBI5.2 (useless), Sterling and Parsons (more helpful in 1st edition, not illustrated in 2nd edition) and are shown at Moth Dissection (reliable).
1. Aedeagus: D.plumbana - tapered without teeth; D.sedatana - 2 tiny dorsal subapical teeth; D.aeratana - 1 tiny dorsal subapical tooth
2. Juxta lobes: D.plumbana/sedatana - triangular and very weakly scobinate; D.aeratana - rounded and strongly scobinate
3. Emargination of ventral margin of valva: D.plumbana/sedatana - narrow; D.aeratana - broad
BTM also emphasises that D.plumbana has a narrower cucullus than in D.sedatana/aeratana and S&P mention that the cucullus is slightly smaller in D.plumbana. The images at Moth Dissection suggest that this difference is sufficiently indistinct that it would be unreliable - it is certainly not nearly as apparent as the illustrations in BTM (p304) would suggest.
(P&M differentiate a further species L.torrana and confusion reigns in any further attempt to differentiate the species from this source: P&Ms male L.torrana is D.plumbana, their female L.aeratana is D.plumbana, their female L.torrana is D.aeratana and their female L,plumbana is D.aeratana - which leaves their male L.plumbana as unmatched).
§1 Franchises Lodge RSPB, Wiltshire; 01/05/2026; male; fw 7.1mm
All images © Chris Lewis
All images © Chris Lewis
Page published 09/05/2026 (§1)
