Costa, 1828
Appearance in life
Scale cover of adult female thin, circular to oval, flat to moderately convex, white or grey, sometimes darker towards centre, with pale to yellow or dark exuviae usually central or subcentral; sometimes concealed under the epidermis of the host. Scale cover of immature male (if present) different from that of female: small, elongate, white and felted, sometimes clearly tricarinate, with apical exuviae.
Morphology
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Adult female not pupillarial; body turbinate or subcircular, slightly swollen in the prosoma, membranous except for pygidium; lateral lobes of free abdominal segments quite well developed, never with marginal sclerotized spurs. Pygidium broad, sometimes with an apical notch formed by divergent median lobes. Median lobes divergent or parallel; although sometimes quite close together, never zygotic; a pair of marginal setae present between them. Second and third lobes smaller than median lobes, often of about equal size, bilobed; fourth lobes reduced, represented by some sclerotization; often a pronounced sclerotized spur present in the position of each fifth lobe. Ventral paraphyses usually present, arising from basal corners of median lobes at least. Gland spines quite small, present singly to just lateral of each third lobe, more numerous on abdominal segments III and IV; absent from between median lobes. Anus oval, situated more or less posterior to centre of pygidium; vulva situated at, or just anterior to, centre of pygidium. Marginal macroducts usually numbering 6 (occasionally more) on either side (1 between median and second lobes, 2 associated with the third lobe, 2 on the fifth segment, 1 on a spur on the fourth segment and occasionally a few more further anteriorly), one usually present between median lobes; each marginal macroduct large, with a thick sclerotized rim and with the long axis of the orifice perpendicular to the pygidial margin. Dorsal macroducts usually of two sizes: two or more large submarginal ducts usually present on segments VI and VII; a much smaller type of duct present in segmental series on pygidium, and in submarginal and submedian groups on prepygidial segments; also sometimes present on segment VI, lateral to anus. Submarginal dorsal bosses usually present. Duct tubercles absent. Perivulvar pores always present in 5 groups. Stigmatic disc pores present by anterior spiracles only. Antenna usually with only 1 seta.