Exochomus Redtenbacher, 1843: 11. TS: Coccinella quadripustulata Linnaeus, 1758.
The single introduced Australian species can immediately be recognized by its elytral pattern, broadly beaded elytral margins, completely recurved abdominal postcoxal lines and strong spical spines on tibial apices.
Length 3-3.7 mm. Dorsum glabrous; elytra black or brown with orange markings; eye distinctly emarginate. Antenna 10-segmented; scape symmetrical; terminal antennomere small and partially embedded in penultimate one. Clypeus short; labrum almost entirely exposed. Pronotal base entirely bordered; prosternal process very narrow, without carinae; hypomeral fovea absent. Protibia simple, narrow; meso- and metatibiae with 2 apical spurs; claw strongly appendiculate. Elytral margin very finely reflexed with complete bead; epipleural fovea absent. Abdomen with 6th ventrite visible in male; abdominal postcoxal lines separated at middle, each arcuately recurving apically and reaching midpoint of lateral line. Male terminalia. Parameres and phallobase symmetrical; penis guide asymmetrical. Parameres articulated with phallobase. Penis stout, consisting of single sclerite; basal capsule distinct and T-shaped. Apodeme of male sternum 9 very narrow and rod-like. Female terminalia. Coxities distinctly elongate, triangular; styli strongly reduced and hardly visible; infundibulum horn-like, with sperm duct originating at its base; sperm duct divided into two regions of different diameter. Spermatheca globular without clear cornu; spermathecal accessory gland distinctly separated from sperm duct.
Distribution and Biology
Worldwide, but because of the problems in the Brumoides-Exochomus complex the generic status of many species is uncertain. Most biological observations are limited to a Palaearctic E. quadripustulatus (L.) which has very broad host and habitat range feeding on aphids and various scales.
Chapin, E. A. 1965. The genera of the Chilocorini (Coleoptera, Coccinellidae). Bulletin of the Museum of Comparative Zoology, 133(4): 227-71.
Redtenbacher, L. 1843. Tetamen dispositionis generum et specierum Coleopterorum Pseudotrimeorum. Archiducatus Austriae, Vindobonae, 32 pp.
Slipinski, S.A. 2007. Australian Ladybird Beetles (Coleoptera: Coccinellidae) their biology and classification. ABRS, Canberra. 286 pp.
Slipinski, A, and J. A Giorgi. 2006. Revision of the Australian Coccinellidae (Coccinellidae). Part 6. Tribe Chilocorini. Annales Zoologici (Warszawa), 56, (2): 265-304.
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