Eriosoma rileyi Thomas

On bark of trunk and branches of small elms (Ulmus americana, rubra) in North America, forming small colonies covered with wax wool very like those of E. lanigerum on apple, and causing similar deformation of woody tissue. It lives all-year-round on elm, without forming leaf-galls. Apterae under the wax are pinkish, yellow or brown; BL 1.8-2.3 mm. Alatae produced in June to August have ANT III 0.8-1.0 × head width across (and including) eyes, with secondary rhinaria rather widely spaced. Sexuparae are apterous, produced in September-October, depositing dwarf sexuales directly onto bark (Patch 1913, Palmer 1952).

- Roger Blackman, Victor Eastop: (2013) Aphids on the world's plants^©

Reference: http://www.aphidsonworldsplants.info/d_APHIDS_E.htm#Eriosoma