Synonyms
Stethorus Weise, 1885: 74. TS: Coccinella minima Rossi, 1794
Allostethorus Iablokoff-Khnzorian, 1972: 121. TS: Stethorus (Allostethorus) amurensis Iablokoff-Khnzorian, 1972
Diagnosis
Stethorus is easily recognized from Parastethorus by its dorsal setae sparse and erect and abdominal postcoxal line recurved and complete. Houston (1980) described some variation in the length of the abdominal postcoxal lines in P. nigripes (Kapur) but this seems to be an unusual exception.
Description
Length 1-2 mm. Body elongate-oval and moderately convex; winged head dorsally not covered by pronotum;; dorsum uniformly hairy. Colour blackish. Head transverse; eyes finely facetted, slightly emarginate. Antenna 11-segmented; shorter than head capsule with scape and pedicel enlarged and subequal; antennomere 3 short; antennal club 3-4-segmented. Terminal maxillary palpomere weakly narrowing apically. Prosternum moderately long in front of coxae, arcuate and somewhat prominent medially; prosternal process narrow without distinct carinae. Anterior margin of mesoventrite straight medially. Tarsi 3-segmented. Mesoventrite broader than coxal diameter; Metaventral postcoxal lines strongly recurved. Elytral epipleuron narrow, incomplete apically, not foveate. Abdominal postcoxal line recurved and complete. Male terminalia. Parameres and phallobase symmetrical; penis guide symmetrical. Parameres articulated with phallobase. Penis stout, consisting of single sclerite; basal capsule weak to absent. Apodeme of male sternum 9 very narrow and rod-like. Female terminalia. Coxities broad plates; styli terminal, well developed, with apical setae; infundibulum absent; sperm duct simple, uniform in diameter. Spermatheca not sclerotised; spermathecal accessory gland distinctly separated from sperm duct.
Distribution and Biology
Numerous species of this genus feed on spider mites (Acari: Tetranychidae); four species are known from Australia.
Genus References
Houston, K J. 1980. A revision of the Australian species of Stethorus Weise (Coleoptera: Coccinellidae). Journal of the Australian Entomological Society, 19: 81-91.
Houston, K J. 1983. Redescription of Stethorus obscuripennis (Lea) (Coleoptera: Coccinellidae) from Norfolk Island. Journal of the Australian Entomological Society, 22: 185-87.
Iablokoff-Khnzorian, S. M. 1972. Novye vidy zhestokrylykh-kokcinellid iz SSSR (Coleoptera, Coccinellidae) [in Russian]. Doklady Akademii Nauk Armyanskoy SSR, 55, (2): 116-22.
Slipinski, S.A. 2007. Australian Ladybird Beetles (Coleoptera: Coccinellidae) their biology and classification. ABRS, Canberra. 286 pp.
Weise, J. 1885. Coccinellidae. Bestimmungstabellen der europaischen Coleopteren. II. Auflage mit Berücksichtung der Arten aus dem Nordlichen Asien. Mödling. 83 pp.
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