Macrosiphum gei apterae are spindle-shaped, usually mid-green to bluish green or wine red.

Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Macrosiphum gei is found in dense colonies on the upper parts of the flower stem of Geum urbanum Herb-Bennet (also known as Wood Avens) and on Hybrid Avens. It can also occur on the undersides of the leaves of some Apiaceae, especially Anthriscus.

Summer.

Status in Britain is difficult to determine due to lack of records.

Status in Leicestershire and Rutland not known.

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