scale insect

kilpikirva Any of the small parasitic insects of the superfamily Coccoidea, that live on plants and sap nutrients from them.
(quote-text)
2008, Nathaniel B. Hardy, Systematic Studies of Scale Insects (Hemiptera: Coccoidea), http://books.google.com.au/books?id=6IsWcxVmrkYC&pg=PA1&dq=%22scale+insect%22%7C%22scale+insects%22&hl=en&sa=X&ei=LTPKUuXIHYmqkwXsiIDABw&redir_esc=yv=onepage&q=%22scale%20insect%22%7C%22scale%20insects%22&f=false page 1,

Scale insects (Hemiptera: Coccoidea) are a diverse group (>7,300 species) of plant parasites that are closely related to aphids. Several species of scale insects are very serious pests of agriculture, whereas others are cultivated for dyes, lacquer, or for use in biological control of invasive plants. All scale insect species in which males occur are sexually dimorphic.