37.009 Coleophora milvipennis (Buff Birch Case-bearer)
ws 10.5-13mm; Jul; birch (Betula spp); locally common on heath and open woodland in England, N.Wales & C.Scotland
Coleophora milvipennis
ID: Plain forewing with a pale costa; antennae not ringed in apical portion > 7 species
Male genitalia: sacculus without a posterior process; sacculus ending in a curved lateral process that comes to a narrow point; subapical process present, about as long as wide > C.milvipennis. 4 species have plain forewing with pale costa and sacculus ending in a pointed lateral process with an additional subapical process. C.adjectella and C.badiipennella have the antenna ringed to the apex and ws 9-10mm (and so should be excluded by fw>5mm). C.alnifoliae has ws 12-13mm and has the antenna unringed in the apical portion; its subapical process is about twice as long as wide. Note that the subapical process is directed medially from the plane of the valva so that its full length cannot be seen with the valva set flat. In the gallery below an image is shown of the valva of §4 orientated to show the full extent of the subapical tooth. In this specimen the subapical tooth is ~1.5x as long as wide. Its aedeagus looks the same as in §1, the image of the aedeagus of C.alnifoliae at Dissection Group shows a more rounded less sclerotised apex and birch are present rather than alder at the trapping site.
Female genitalia: Subgenital plate transverse; introitus not sclerotised; ostium arising from incision in posterior margin which extends almost to anterior margin; signum moderate, base plate with irregular margin, spike as long as base plate.
Male genitalia: sacculus without a posterior process; sacculus ending in a curved lateral process that comes to a narrow point; subapical process present, about as long as wide > C.milvipennis. 4 species have plain forewing with pale costa and sacculus ending in a pointed lateral process with an additional subapical process. C.adjectella and C.badiipennella have the antenna ringed to the apex and ws 9-10mm (and so should be excluded by fw>5mm). C.alnifoliae has ws 12-13mm and has the antenna unringed in the apical portion; its subapical process is about twice as long as wide. Note that the subapical process is directed medially from the plane of the valva so that its full length cannot be seen with the valva set flat. In the gallery below an image is shown of the valva of §4 orientated to show the full extent of the subapical tooth. In this specimen the subapical tooth is ~1.5x as long as wide. Its aedeagus looks the same as in §1, the image of the aedeagus of C.alnifoliae at Dissection Group shows a more rounded less sclerotised apex and birch are present rather than alder at the trapping site.
Female genitalia: Subgenital plate transverse; introitus not sclerotised; ostium arising from incision in posterior margin which extends almost to anterior margin; signum moderate, base plate with irregular margin, spike as long as base plate.
Dissection
Male genitalia
Female genitalia
§6 I have identified this as C.milvipennis but am not completely sure it isn't C.limosipennella. There are certainly birch at Winterton and I didn't notice any elm. Several similar Coleophoras obtained at Winterton all proved to be C.milvipennis. The key differentiation between these species is that the antenna is ringed to the apex in C.limosipennella and the barring fades at 3/4 in C.milvipennis. In this specimen the barring does fade but is still discernible at the apex. The image of the female genitalia of C.milvipennis at Moth Dissection shows a similar subgenital plate and ostium to §6 (as does §2 above), but the signum of §6 shows a distinctly longer spike than the base plate and the base plate does not look particularly irregular - these features of the signum are those I have suggested as distinguishing the female genitalia of these 2 species. However, the illustration of the signum of C.limosipennella in MBGBI3 shows a shorter, stouter more gradually tapering thorn and there is no image at Moth Dissecton for comparison.
§1 Winterton, Norfolk; 11/06/2015; male; fw 6.1mm; to light
§2 Winterton, Norfolk; 11/06/2015; female; fw 5.9mm; to light
§3 Winterton, Norfolk; 11/06/2015; male; fw 6.0mm; to light
10 live specimens photographed from Winterton but they appear so similar that I cannot be sure which of them have been dissected
§4 Belfairs, Essex; 30/06/2015; male; fw 5.8mm; to light
§5 Winterton, Norfolk; 09/07/2015; male; fw 6.1mm; to light
§6 Winterton, Norfolk; 06/08/2015; female; fw 5.4mm; to light
§7 Winterton, Norfolk; 06/08/2015; female; fw 5.2mm; to light
All images © Chris Lewis
§2 Winterton, Norfolk; 11/06/2015; female; fw 5.9mm; to light
§3 Winterton, Norfolk; 11/06/2015; male; fw 6.0mm; to light
10 live specimens photographed from Winterton but they appear so similar that I cannot be sure which of them have been dissected
§4 Belfairs, Essex; 30/06/2015; male; fw 5.8mm; to light
§5 Winterton, Norfolk; 09/07/2015; male; fw 6.1mm; to light
§6 Winterton, Norfolk; 06/08/2015; female; fw 5.4mm; to light
§7 Winterton, Norfolk; 06/08/2015; female; fw 5.2mm; to light
All images © Chris Lewis
Page published 30/08/2015 (§1-4) | §5 added 01/01/2016 | §6 added 09/01/2016 | §7 added 13/01/2016
