73.292 Mythimna (Mythimna) favicolor (Mathew's Wainscot)
ws: 34-42mm (MBGBI9.1), fw: 16-18mm (Waring & Townsend); Jun-Jul, occasionally bivoltine Sep; common saltmarsh grass (Puccinellia maritima); NS-B in saltmarsh on S&E coasts of England.
Mythimna (Mythimna) favicolor (Mathew's Wainscot) §1 male
ID: Very similar to M.pallens (Common Wainscot) (and some believe it to be a saltmarsh variant of M.pallens). M.favicolor averages slightly larger but most specimens will be in the overlap range. There does not seem to be an absolutely relible means of distinguishing these 'species' but, in addition to a saltmarsh habitat, the following may help: 1) Forewing ground colour - usually sandy-orange or straw in M.favicolor, usually pale straw or reddish-brown in M.pallens; 2) Veins - are not pale-marked or are indistinctly pale-marked in M.favicolor, usually distinctly pale-marked in M.pallens; 3) Postmedian line of dots - this is quite variable in both species but is usually represented by at least 2 dots in M.favicolor, whilst it is not infrequently absent in M.pallens; 4) Hindwing upperside - said to be usually off-white with grey streaks in M.favicolor, white with a variable grey suffusion in M.pallens (but I think M.pallens is so variable with respect to this feature that it cannot be used as an aide to identifying M.favicolor. There are no genital differences between M.favicolor and M.pallens.
Dissection
Male genitalia
Female genitalia
§1 Foulness, Essex; 28/06/2008; male; fw 18.2mm
§2 Foulness, Essex; 03/07/2010; female; fw 17.6mm
§3 Foulness, Essex; 27/06/2015; female; fw 16.3mm
§4 Foulness, Essex; 27/06/2015; male; fw 16.2mm
§5 Foulness, Essex; 03/08/2018; male; fw 13.8mm!
All images © Chris Lewis
§2 Foulness, Essex; 03/07/2010; female; fw 17.6mm
§3 Foulness, Essex; 27/06/2015; female; fw 16.3mm
§4 Foulness, Essex; 27/06/2015; male; fw 16.2mm
§5 Foulness, Essex; 03/08/2018; male; fw 13.8mm!
All images © Chris Lewis
Page published 27/12/2016 (§1-4) | §5 added 18/02/2019
