MacGillivray, 1921
Appearance in life
Scale cover of adult female elongate, shaped like a rather broad mussel shell, more or less convex, margin sometimes slightly irregular; pale, with apical exuviae. Scale cover of immature male different from that of female; small and elongated, white, felted, with terminal exuviae.
Morphology
Adult female not pupillarial; body elongate-fusiform, widest at metathorax or abdominal segment I or II, then tapering to apex of pygidium. Derm membranous except for pygidium; free abdominal segments weakly to moderately produced laterally, without marginal sclerotized spurs. Pygidium rounded. Median lobes small, non-zygotic, widely separated, often divergent; each lobe more or less conical, occasionally irregularly dentate; without distinct marginal setae between the bases. Second lobes similar to median lobes, bilobed; third lobes absent. Ventral paraphyses absent. Gland spines on pygidium slender, elongate, absent from between median lobes; usually present singly or in pairs on pygidial segments; on prepygidial segments anterior to segment IV sometimes more numerous, shorter (conical duct tubercles) and ventral, present as far forward as segment I and often on meso- and metathorax. Anus circular, usually situated near anterior 1/3 of pygidium; vulva also situated near anterior 1/3 of pygidium. Marginal macroducts about same size as dorsal ducts, each thickly sclerotized around the orifice; long axis of orifice perpendicular to margin; sometimes associated with marginal serrations; usually numbering about 6 on each side of the pygidium; absent from between median lobes. Dorsal macroducts about same size as marginal ducts, arranged in segmental series or rows of submarginal and (on some abdominal segments) submedian ducts; present as far forward as abdominal segment I or even prothorax, and as far posteriorly as submargin of segment VIII, but submedian ducts absent from segments VII or VIII; sometimes almost scattered on pygidium. Ventral conical duct tubercles present anterior to abdominal segment IV. Perivulvar pores present in 5 groups. Stigmatic disc pores present in a small cluster by anterior spiracle, and a few present by posterior spiracle. Antennae well separated, each normally with 1 seta.