Common Dogwood-grass Aphid Anoecia corni

Some Niger appeared in my un-mown lawn in 2023, presumably from bird food put out at least two winters before. I checked it for any insects and found a single winged aphid. I couldn't find any species listed as occurring on Niger but it was a disticntive-looking aphid so I thought I might be able to get an ID. After a bit of searching I came across this species but noted that there were similar Anoecia species that needed to be eliminated.

The Blackman, Dransfield & Brightwell key provides information about how to identify corni. The presence of flat round tubercles on segments including 5 & 6 eliminated furcata (assuming I identified the tubercles correctly - I'd expected them to be on the upper side but they were at the edges of the sternites). I think the detail of the rhinaria and the relative length of the rostral and tarsal segments were sufficient to eliminate both vagans and major.

Common Dogwood-grass Aphid Anoecia corni cleared abdomen side from below, hind tarsus, rostrum and antenna, North Elmham (Norfolk, UK), 19th August 2023