What Bug Is That? The guide to Australian insect families.

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The Australian species are placed in 5 subfamilies. Pelecotominae and Ptilophorinae include the least specialised forms, in which the adults have complete elytra and minor sexual dimorphism and the larvae are probably predators or ectoparasitoids of wood-boring larvae; Trigonodera is included in the former group, Ptilophorus in the latter. In Hemirhipidiinae ( Nephrites and Sitarida ), the antennal dimorphism is slight but the elytra are abbreviated; larvae are not known, but S. scabriceps was reared from a beetle-infested Acacia log. In Rhipiphorinae, the male antennae are biflabellate, while those of the female are pectinate, and the elytra are either dehiscent and more or less acute at apex ( Macrosiagon ) or very short ( Rhipiphorus ). Rhipiphorines lay their eggs in flowers, on the undersides of leaves or in soil, and the 1st instar triungulins attach themselves to solitary bees ( Rhipiphorus ) or wasps of the families Vespidae, Sphecidae, Tiphiidae or Scoliidae ( Macrosiagon ). These minute larvae enter the nest with the female and eventually bore into the hymenopteran larvae. This endoparasitic phase is followed by an ectoparasitic one, in which the larva leaves the body of the host and feeds externally. In Rhipidiinae, the male is small and midge-like, with very short elytra and large eyes; the female is larviform, without elytra or hind wings. Rhipidiine triungulins attach themselves to cockroach nymphs, pierce the cuticle and feed externally for a short time, and then bore into the host to become endoparasitic. Riekella are parasites of Blattidae, Paranephrites xenus has been reared from Blaberidae, and all other genera, including Rhipidioides , have been associated with Blattellidae. [Besuchet 1956a; Callan 1981; G. V. Hudson 1934; Linsley et al. 1952; Riek 1955, 1973; Selander 1957.]


Elongate beetles, often laterally compressed and posteriorly tapered, as in Mordellidae, but without abdominal spine. Body often subglabrous or clothed with decumbent hairs; head may be strongly deflexed and abruptly constricted behind eyes to form neck, which may or may not be visible; eyes slightly to strongly emarginate and sometimes very large; elytra may be entire and slightly dehiscent, exposing the abdominal apex, or highly reduced exposing most of abdomen. Females of Rhipidiinae lack both elytra and hind wings and have reduced mouth-parts.

Known larvae are usually very lightly sclerotised parasitoids, but in Rhipiphorinae and Rhipidiinae the 1st instars are minute, well sclerotised triungulins.

  • Trigonodera sp.