Walsh, B.D. 1868 Insects infesting the apple. -- on the bark. [Chapter VIII.- The oyster-shell bark-louse (Aspidiotus conchiformis), Gmelin].. First Annual report on the noxious insects of the State of Illinois. 34-53.

Notes: The history, biology, distribuion from tree to tree, natural enemies and chemical control of A. conchiformis is discussed. Other species mentioned include (A. pinifoliae, new sp. and A. salicis-nigrae.