41.001 Blastobasis phycidella (Southern Masoner)
ws: 17-19mm (Hants Moths), fw 8mm (Manley); detritus; 4 specimens taken in Southampton 1930, resident on Guernsey since 1990.
Blastobasis phycidella §1 male (image by Bill Crooks)
ID: Separated in the key in MBGBI4.1 (p197) on basis of grey forewing ground colour and transverse (rather than oblique) dorsal strigula (when present); however, neither of these features seem to be reliable due to the extreme variablity of B.adustella. Both B.phycidella and B.glandulella have an appendage at the base of the antenna (at the junction of scape and pedicel); as far as I have been able to establish this appendage is absent in B.adustella, B.lacticolella and B.rebeli and less well-developed in B.vittata.
Male genitalia: Blastobasis species are very similar. The uncus and a midline projection from the ventral surface of the posterior margin of the tegumen are important features to see well. Since the uncus is naturally curved ventrally it is inevitably distorted in setting it and some apparent intraspecific variability arises from variability in the amount of distortion. And since the origin of the uncus is dorsal to the midline projection from the ventral edge it can be problematic to show both well in the same image.
B.phycidella vs B.glandulella and B.lacticolella: uncus clubbed vs broad-based and tapering to a rounded apex.
B.phycidella vs B.adustella and B.lacticolella: ventral (saccular) margin of the valva almost straight vs distinctly curved/angular.
The uncus of B.adustella also appears longer with a longer narrow base and a more obviously clubbed apex.
B.phycidella vs B.vittata: median projection from posterior margin of tegumen short, narrow, angular and notched vs longer, broader, rounded with a shallow apical concavity. The uncus of B.vittata is almost parallel-sided / only very slightly clubbed
B.phycidella vs B.rebeli: uncus clubbed vs uncus with a rounded broad basal ⅓ abruptly narrowing to an almost parallel-sided / only slightly clubbed apical ⅔. The ventral (saccular) margin of the valva is gently curved.
B.maroccanella has a very long uncus with a narrow basal half, broader apical half and the medial projection of the tegumen is long and rounded (based on a single image at Moth Dissection)
The straight valval margin of B.phycidella ends in a much more abrupt distal angulation as it turns towards the apical valval process than is seen in any of the other species.
Female genitalia: Female genitalia are illustrated in MBGBI4.1 (p198) and show extremely long posterior apophyses with a PP:AP ratio of 3.3 and a very long narrow ductus bursae; and possibly the signum has a straighter thorn than in other species. Specimen awaited before further elucidation.
Male genitalia: Blastobasis species are very similar. The uncus and a midline projection from the ventral surface of the posterior margin of the tegumen are important features to see well. Since the uncus is naturally curved ventrally it is inevitably distorted in setting it and some apparent intraspecific variability arises from variability in the amount of distortion. And since the origin of the uncus is dorsal to the midline projection from the ventral edge it can be problematic to show both well in the same image.
B.phycidella vs B.glandulella and B.lacticolella: uncus clubbed vs broad-based and tapering to a rounded apex.
B.phycidella vs B.adustella and B.lacticolella: ventral (saccular) margin of the valva almost straight vs distinctly curved/angular.
The uncus of B.adustella also appears longer with a longer narrow base and a more obviously clubbed apex.
B.phycidella vs B.vittata: median projection from posterior margin of tegumen short, narrow, angular and notched vs longer, broader, rounded with a shallow apical concavity. The uncus of B.vittata is almost parallel-sided / only very slightly clubbed
B.phycidella vs B.rebeli: uncus clubbed vs uncus with a rounded broad basal ⅓ abruptly narrowing to an almost parallel-sided / only slightly clubbed apical ⅔. The ventral (saccular) margin of the valva is gently curved.
B.maroccanella has a very long uncus with a narrow basal half, broader apical half and the medial projection of the tegumen is long and rounded (based on a single image at Moth Dissection)
The straight valval margin of B.phycidella ends in a much more abrupt distal angulation as it turns towards the apical valval process than is seen in any of the other species.
Female genitalia: Female genitalia are illustrated in MBGBI4.1 (p198) and show extremely long posterior apophyses with a PP:AP ratio of 3.3 and a very long narrow ductus bursae; and possibly the signum has a straighter thorn than in other species. Specimen awaited before further elucidation.
§1 Dagenham, Essex; 24/06/2026; male; fw 7.6mm; specimen provided by Bill Crooks; first British record away from the Channel Islands since 1930
All images © Chris Lewis
All images © Chris Lewis
Page published 19/08/2026 (§1)
