Cockerell, 1897
Appearance in life
Scale cover of adult female very thick, hard and brittle, circular, weakly to strongly convex, greyish brown to black, with black central or subcentral exuviae; ventral scale dark, thick and hard around margins, thin in centre. Scale cover of immature male similar to female but smaller, oval with exuviae towards one end.
Morphology
Adult female not pupillarial; body roughly circular or ovoid or pyriform; prosoma usually membranous, in a few species somewhat sclerotized, especially towards the margins. Marginal tubercles or spurs absent from prosoma in most species. Pygidium short and wide, projecting little, apical angle obtuse, with a distinctive pattern of sclerotization: across apex of pygidium between third lobes and forward to anterior margin of pygidium; a pair of small areas, each arising from base of third lobe and extending forward a short distance before curving laterally; and another pair of sclerotized areas, each arising near base of fourth lobe and expanding laterally; margin sclerotized and sometimes irregular or toothed. Pygidium with 4 pairs of unilobulate lobes, the fourth pair sometimes reduced to sclerotized points; lobes often notched, especially on outer margins, each of which may have several notches especially on outer lobes; margin anterior to fourth lobes crenulate or somewhat toothed, more or less sclerotized. Lobes parallel to longitudinal axis, well sclerotized; median lobes narrower than second or third lobes; median lobes not obviously elongate. Conspicuous paraphyses or scleroses, variously shaped, arising from bases of lobes, in the interlobular space between second and third lobes, and from a short section of margin anterior to fourth lobe; at least some paraphyses as far laterally as third lobes usually much longer than a median lobe. Plates small to minute, sometimes slightly fringed, shorter than or as long as lobes, those between the lobes slightly fringed in some species; usually 0 (occasionally 2) present between median lobes; 0, 1 or 2 between median and second lobes; 0 - 3 between second and third lobes; 0 - 4 between third and fourth lobes; and a few small projections occasionally present anterior to fourth lobe. Anus oval to circular, small (usually shorter than median lobe), often situated near centre of pygidium, but in some species located in posterior quarter; vulva often situated approximately at centre of pygidium but in some species, may be as far forward as anterior quarter of pygidium. Dorsal macroducts usually very long and slender, and moderate in number; 0 or 1, occasionally 2 marginal ducts between median lobes, 0 - 1 between median and second lobes, 1 or 2 between second and third lobes and 1 - 3 between third and fourth lobes on either side; a series of marginal ducts often present along pygidial margin anterior to fourth lobe, sometimes along the ventral margin as well. Submarginal ducts often sparse, occasionally absent; usually arranged in 3 poriferous furrows or intersegmental series between segments VIII and VII, VII and VI and VI and V on each side. Ventral prepygidial marginal ducts often present. Lateral margins of prepygidial segments and even sometimes of thorax frequently crenulate and bearing a series of minute ducts. Perivulvar pores absent or present in 3-5 groups. Stigmatic disc pores absent; antennae situated fairly near mid-line, each bearing one seta and a small, sclerotized spur.