Dragonflies: Hemicordulia tau

Damselflies Austroagrion cyane Austroagrion watsoni Austroargiolestes calcaris Austrocnemis splendida Austrolestes annulosus Austrolestes aridus Austrolestes cingulatus Austrolestes io Austrolestes leda Austrolestes psyche Coenagrion lyelli Hemiphlebia mirabilis Ischnura aurora Ischnura heterosticta Pseudagrion microcephalum Xanthagrion erythroneurum Dragonflies Anax papuensis Archaeosynthemis orientalis Austroaeschna ingrid Austroaeschna multipunctata Austroaeschna unicornis Austrogomphus guerini Austropetalia tonyana Austrothemis nigrescens Crocothemis nigrifrons Dendroaeschna conspersa Diplacodes bipunctata Diplacodes haematodes Diplacodes melanopsis Diplacodes trivialis Eusynthemis virgula Hemicordulia australiae Hemicordulia tau Notoaeschna sagittata Orthetrum caledonicum Parasynthemis regina Petalura gigantea Procordulia jacksoniensis Synthemis eustalacta Telephlebia brevicauda
distribution map
Source: ALA

♀ Emerald, VIC

♂ Narawntapu NP, TAS

♀ Milicent, SA

♂ Grampians, VIC
more
Common Nametau emerald
FamilyCorduliidae
Genus/SpeciesHemicordulia tau (Selys, 1871)
Abundance &
Distribution
Found throughout Australia and very common in the southern half of the country, including Tasmania and at high altitudes.
HabitatFound at a variety of still and sluggish water and occasionally rivers. Adults are vagrants that disperse widely and can readily be found in swarms away from water.
Description &
Identification
These are medium-sized dragonflies, usually with brown eyes and body coloration and pattern typical of "emeralds" — predominantly black along the top of the abdomen but with yellow markings curved up on the side. The side of the thorax for most emeralds is predominantly yellow with two or three dark, diagonal bands. The abdomen on males is thicker in the middle while for females it is thick at the base and evenly tapered to a thinner end.
Similar SpeciesVery similar to Hemicordulia australiae from which it can tentatively be separated by having pale pterostigma and wing veins on the leading edges where these are black for mature H. australiae. Definite identification can be made by viewing the coloration on top of the frons ("nose"); H. australiae has an indistinct dark patch while H. tau has a distinct inverted "T" shape. In the northern half of Australia there are several other Hemicordulia species but the patterns on the abdomen (tail) are noticeably different. Hemicordulia emeralds are also somewhat similar to Procordulia (swamp emeralds) that however lack the upward curving yellow markings along the tail.
Behaviour &
Observations
Males will patrol around water, typically flying continuously around half a metre above the surface and periodically hovering. They perch hanging vertically from vegetation or sometimes near horizontally when attached to a more sturdy object. Like all the emeralds, after mating the pair separate and females oviposit in flight, dipping their tail briefly into water.
LinksBrisbane Insects
Esperance Fauna

Page Updated: 31-Mar-2016
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