MacGillivray, 1921
Appearance in life
Scale cover of adult female circular to oval, convex, thick, with subcentral exuviae and a strong ventral scale. Scale cover of immature male similar to female but smaller, oval with exuviae towards one end.
Morphology
Adult female not pupillarial; body circular or pyriform; prepygidium often expanded but never forming lateral lobes, membranous except for slight marginal sclerotization in a few species. Pygidium partly sclerotized; quite acute in some species, with angle at apex sometimes as narrow as 90°. Pygidium with prominent median lobes only, these somewhat elongate, often slightly convergent, with the inner margins very close together; each lobe with a well-defined basal sclerosis; other lobes absent. Paraphyses present on the margins of segments VII and VI. The largest paraphysis may be as long as or longer than a median lobe, and arises just lateral to the outer basal angle of each median lobe, and is clavate. In many species, the clavate end of this paraphysis is a subcircular knob that is almost detached from the stem (the knob often bulges towards the midline), but in some species the paraphysis is just markedly swollen at the inner end. Dorsal marginal setae flagellate; seta at outer corner of each pygidial segment long, sometimes longer than a median lobe. Plates small and slender, shorter than lobes in many species, usually simple with pointed tips (resembling gland spines), but slightly fringed in a few species; absent from between median lobes except in one species; occasionally present as far forward as segment V. Anus smaller than median lobe, oval, situated within 2-3 of its diameters of apex of pygidium; vulva situated approximately at middle of pygidium, sometimes slightly closer to pygidial apex than to the base. Dorsal macroducts very slender, of moderate length; 1 marginal duct present between median lobes; submarginal ducts usually present, sometimes arranged in intersegmental rows. Preygidium sometimes with marginal macroducts on some abdominal segments; without plates or duct tubercles. Perivulvar pores usually few, arranged in 4 or 5 groups, or absent. Stigmatic disc pores absent; antennae quite widely spaced, each bearing 1 seta and a more or less developed, sclerotized spur.