McClure, M.S. 1988 The armored scales of hemlock.. Dynamics of Forest Insect Populations: Patterns, Causes, Implications. Plenum Press New York

Notes: Two scale species investigated: Fiorinia externa and Nuculaspis tsugae; distribution; biology and life history; hosts; interspecific competition and competitive exclusion; interactions with natural enemies, the most important of which is Aspidiotiphagus citrinus; host vigor, stress, and scale fitness.