047 Nycterosea obstipata (Gem)

GEOMETRIDAE | Larentiinae | Xanthorhoini

70.047 Nycterosea obstipata (Gem)

ws: 18-21mm (ukmoths*); Apr-Nov; migrant in variable numbers with breeding in some years
* Waring gives fw 12-14mm but this is surely wrong; fw expected for the quoted ws would be 8.5-10.5mm; fw of my specimens range 10.0-11.7mm

Nycterosea obstipata (Gem) §1 male

ID: Sexually dimorphic. Male characterised by a dark central irregular forewing cross-band which varies in width between individuals to some extent and fades with wear; black central spot may be obscured by the central cross-band or outlined by a pale halo; short dark apical streak. Female has more evenly coloured, more red-brown forewing; darker central cross-band still discernable; central black spot small but outlined by a prominent bold white halo.

Variation
Dissection
Male genitalia
Female genitalia

§1 St Marys, Isles of Scilly; 26/10/2007; male; fw 10.0mm
§2 St Marys, Isles of Scilly; 03/10/2011; female; fw 11.7mm
§3 St Marys, Isles of Scilly; 02/10/2011; male; fw 10.4mm
§4 St Marys, Isles of Scilly; 19/10/2013; male; fw 10.5mm
§5 St Marys, Isles of Scilly; 07/10/2016; male; to light
§6 St Marys, Isles of Scilly; 07/10/2016; female; fw 11.6mm; to light
§7 St Marys, Isles of Scilly; 11/10/2016; male; fw 11.9mm; to light
§8 St Marys, Isles of Scilly; 12/10/2018; female
§9 St Marys, Isles of Scilly; 19/10/2018; male
§10 St Marys, Isles of Scilly; 11/10/2019; female
§11 Foulness, Essex; 14/08/2021; male
§12 Foulness, Essex; 09/09/2023; male
All images © Chris Lewis