The ground colour in tristella varies considerably and the one shown below is a particularly dark specimen. The light streak is creamy-coloured, narrows at one-third and branches into four fairly obvious 'fingers' at two-thirds, while the termen (end of wing) has a fairly rounded appearance.
Agriphila tristella, Westcott 9th August |
The ground colour in selasella is fairly consistently a sandy brown colour. The light streak is white with a noticeable thin black line on the costal (lower) side, doesn't narrow at one-third, the branching into 'fingers' at two-thirds is less obvious and the termen is more substantial and squared in appearance.
Agriphila selasella, Westcott 9th August |
The facial cone in tristella is normally more substantial too but that's not a particularly reliable feature because it can become worn quite quickly.
Dave Wilton
Westcott, Bucks
A very useful reminder Mister Wilton
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