Archaeosynthemis leachii is a species of dragonfly of the family Synthemistidae,[3] known as the twinspot tigertail.

[4] It is a medium-sized dragonfly with black and yellow markings.

It inhabits streams, seepages and swamps in south-western Australia.

[5][6] Archaeosynthemis leachii was originally named Synthemis leachii, and has also been known as Synthemis martini.

[7]