73.170 Mesapamea didyma (Lesser Common Rustic)
fw: 11-16mm; Jul-Aug; grasses (Poaceae); common throughout GB.
Mesapamea didyma (Lesser Common Rustic) §4 male
ID: Forewing colour and markings extremely variable; kidney mark usually white with a white ring around it. Rounded forewing apex and smoothly curved termen distinguish it from Helotropha leucostigma (Crescent) and Amphipoea species (Ear moths) which have a pointed apex and a fairly straight termen. A.unanimis (Small Clouded Brindle) flies May-Jul, has two basal streaks, central and dorsal, the central of which is usually lacking in Mesapamea species; a crescent-shaped mark on the hindwing, better marked on the underside, is larger and broader in A.unanimis. Genital examination is required to separate M.didyma from M.secalis (Common Rustic) - see Mesapamea
Male genitalia: clavus weakly sclerotised at the apex; cornutus long and narrow. its apical ~2/5 free from tethering to the vesica.
Female genitalia: swelling of posterior ductus bursae faces left (in standard ventral view with the ovipositor up).
Male genitalia: clavus weakly sclerotised at the apex; cornutus long and narrow. its apical ~2/5 free from tethering to the vesica.
Female genitalia: swelling of posterior ductus bursae faces left (in standard ventral view with the ovipositor up).
§1 Strumpshaw Fen, Norfolk; 26/07/2012; male; fw 14.4mm
§2 Strumpshaw Fen, Norfolk; 27/07/2012; male
§3 Skye; 04/08/2013; female; fw 14.3mm
§4 Foulness, Essex; 19/07/2014; male; fw 13.8mm
§5 Compton Bishop, Somerset; 24/08/2014; female; fw 14.6mm
§6 Compton Bishop, Somerset; 24/08/2014; female; fw 14.1mm
§7 Bampton Grange, Cumbria; 01/08/2017; male; fw 14.4mm
§8 Stour Wood, Essex; 14/07/2021; female; fw 14.7mm; to light
§9 Westcliff-on-sea, Essex; 19/08/2021; female; fw 14.6mm
§10 Westcliff-on-sea, Essex; 14/08/2024; male; fw 14.5mm
All images © Chris Lewis
§2 Strumpshaw Fen, Norfolk; 27/07/2012; male
§3 Skye; 04/08/2013; female; fw 14.3mm
§4 Foulness, Essex; 19/07/2014; male; fw 13.8mm
§5 Compton Bishop, Somerset; 24/08/2014; female; fw 14.6mm
§6 Compton Bishop, Somerset; 24/08/2014; female; fw 14.1mm
§7 Bampton Grange, Cumbria; 01/08/2017; male; fw 14.4mm
§8 Stour Wood, Essex; 14/07/2021; female; fw 14.7mm; to light
§9 Westcliff-on-sea, Essex; 19/08/2021; female; fw 14.6mm
§10 Westcliff-on-sea, Essex; 14/08/2024; male; fw 14.5mm
All images © Chris Lewis
Page published 10/04/2016 (§1-6) | §7 added 18/03/2018 | §8 added 12/08/2021 | §9 added 14/12/2021 | §10 added 15/10/2024
