Immature Myzocallis castanicola are yellowish-white or greenish-white with some brown-black dorsal markings. All adults are winged, yellow with paired black spots on the abdomen and a central dark median line on the head. The wing venation distinctly outlined in brown and forewing veins ending in brown spots.  The brown wing outline distinguishes it from other Oak feeding aphids in this genus.

Please provide clear photographs showing adult wing detail.

Found on the undersides of leaves of many chestnut (Castanea) and oak (Quercus) species. It is often abundant on Sweet Chestnut (C. sativa)

Summer.

Not ant attended.

True status in Britain is difficult to determine due to lack of records.

Status in Leicestershire and Rutland not known.

https://influentialpoints.com/Gallery/Myzocallis_castanicola_Sweet_chestnut_aphid.htm