The image Stebbins provides for this species resembles a Harmandiola midge gall more than any other Pemphigus species. The undescribed midge that most closely conforms to Stebbins' description is p-tremuloides-pouch-gall. Since this aphid is not listed in any later summaries of the genus Pemphigini, this may be a mistaken ID. Aphids are known to colonize midge galls on poplar after the midges depart, so there is a plausible reason this error could have been made.