35.132 Caryocolum fraternella (Douglas, 1851)

C. viscariella is slightly larger but has considerable overlap in size (wingspan 10-14mm as opposed to 9-13mm in C. fraternella). The dark bar on the forewing from the costa (leading edge) to the fold (near the middle) is usually lost in the general dark colouration extending along the costa in C. fraternella whereas it can be seen to reach the costa in most fresh C. viscariella. The warm yellow lower surface of segment two of the labial palps in C. fraternella is distinctive to that species in Britain whereas in C. viscariella it is yellowish-cream coloured below with heavily blackish brown mottling.

C. alsinella also has significant overlap in size but is generally smaller. C. fraternella has more extensive orange-brown scaling and usually the costal and tornal spots are separated.

Dark specimens of C. marmorea usually have the costal and dorsal white spots much reduced and the underside of segment two of the labial palps is usually ochreous.

Genitalia differences between the three species above and C. fraternella are distinctive and should be used to confirm an identification when worn specimens are encountered or there is any uncertainty due to the variability of forewing markings and size.