Length 9 mm. Brown pigment in the mesial face of cerata (1).
The pale dorsolateral bands (2) reduce the visible brown to resemble the outline of the A. pluma stem when viewed dorsally.
Anal papilla (3).
Many brown pigment marks on surface of cerata (4).
Small, black, internal eye indistinctly visible (5).
Menai Strait, Wales. August 2010.