Drake, C.J. 1934 Report of the State Entomologist.. Thirty-fifth Annual Year Book (Iowa) Part 4: 71-77.

Notes: Chionaspis americana is the only scale mentioned by species name; San Jose scale, Forbes or cherry scale, Putnam scale, oyster shell scale, European elm scale, scurfy scale, white pine scale, spruce bud scale, and pine tortoise scale also mentioned; notes on hosts.