Pacific Hawaiian damselflies are now believed to be limited to the islands of Maui and Molokai and one population found in 1998 on Hawaii island. The Pacific Hawaiian damselfly was first described by McLachlan (1883, p. 234), based on specimens collected by R.C.L. Perkins from streams on the islands of Lanai and Maui. This damselfly is a relatively small, dark colored species, with adults measuring 1.3 to 1.4 in (34 to 37 mm) in length and having a wingspan of 1.3 to 1.6 in (33 to 42 mm). Both adult males and females are mostly black in color. Males exhibit brick-red striping and patterns, while females exhibit light-green striping and patterns. The only immature individuals of this species that have been collected were early instar (an intermoult stage of development) individuals, and they exhibit flattened, leaf-like gills (Polhemus and Asquith 1996, p. 83). Pacific Hawaiian damselflies are distinguished from other Hawaiian damselflies by the long lower abdominal appendages of the male (USFWS 2010). Pacific damselflies do not disperse over long distances compared to other Hawaiian damselfies (Jordan et al 2007, USFWS 2011).