ErithionyxBlackburn
Updated September 2007.

Synonyms
Erithionyx Blackburn, 1892b: 259. TS: Rhizobius lanosus Blackburn, 1892a.

Diagnosis
Erithionyx and Rhyzobius share coarsely facetted eyes, long 11-segmented antennae and setose dorsum. Erithionyx is distinguished by its more convex densely setose dorsum, single spur on tibial apices and sexually dimorphic claws.

Description
Length 3.0-4.5 mm; head dorsally partially covered by pronotum; dorsum densely, uniformly hairy; vestiture yellow or white. Elytral colour blackish without colour pattern. Eyes coarsely facetted, not or weakly emarginate. Antenna 11-segmented; almost as long as head capsule; antennomere 3 long; antennal club 3-segmented. Terminal maxillary palpomere weakly expanded apically. Prosternum moderately long in front of coxae; prosternal process broad with distinct and complete carinae. Anterior margin of mesoventrite emarginate medially. Mesoventrite narrower than coxal diameter; Metaventral postcoxal lines recurved. Elytral epipleuron narrow, incomplete apically, not foveate. Mid and hind tibiae with single apical spur; claws sexually dimorphic, appendiculate in female, bifid on first and second pairs of legs. 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 distinct and T-shaped. Apodeme of male sternum 9 broad and plate-like. Female terminalia. Coxities distinctly elongate, triangular; styli absent; infundibulum absent; sperm duct simple, uniform in diameter. Spermatheca worm-like, without clear ramus or nodulus; spermathecal accessory gland adjacent to sperm duct.

Distribution and Biology
Erithionyx is endemic to eastern Australia with 2 species distributed from northern New South Wales to as far north as Cairns. One species has been reared from Eriococcus scales; most of the specimens have been collected from vegetation or in flight intercept taps along the rainforest edges.

Genus References
Blackburn, T. 1892a. Further notes on Australian Coleoptera, with descriptions of new genera and species. XI. Transactions of the Royal Society of South Australia, 15(1): 20-73.

Blackburn, T. 1892b. Further notes on Australian Coleoptera, with descriptions of new genera and species. XII. Transactions of the Royal Society of South Australia, 15(2): 207-61.

Slipinski, S.A. 2007. Australian Ladybird Beetles (Coleoptera: Coccinellidae) their biology and classification. ABRS, Canberra. 286 pp.

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