A flash of blue is usually the only sign of a satinwing as one approaches jungle streams hemmed by rampant vegetation. Restricted to clear brooks with log jams and fringing detritus in which their nymphs reside, Euphaea impar is a beauty at home in beastly parts, a body of refractive lightness that haunts the radiant gaps of diffused swamps. The males are reputed to be nervous creatures with little tolerance for intrusions into their territories; their default response to breaches of their personal space is to flutter upwards, turning near-invisible the moment they leave their sunspot to ascend into the canopy. Females are even scarcer; their olive-green bodies and clear wings offer scant contrast against the dull understorey of waterlogged forests.
Euphaeidae is a small family of odonates with stout limbs and stalkless wings. Only three species are known from the Malay Peninsula, but in Borneo, millennia of isolation from the asiatic mainland have caused a modest explosion into at least eight species, including five island endemics. Four of these are congeners of impar, but bear extensive patches of metallic blue-green on their hindwings. This feature invites confusion with metalwing demoiselles, but the latter group can be distinguished by their long, spidery legs and a preference for riffles and bouldery rapids, while euphaeids are more wont to rest on riparian foliage by quieter creeks. Another species closely resembles its more widespread cousin, but lacks dark wing markings and has only been found in Brunei and the Lambir Hills of Sarawak.
A second Euphaeid genus, Dysphaea, consists of heavily built damselflies with the habit of spreading out their purplish wings at rest in the manner of typical anisopterans. Recorded more than 150 years ago in Singapore, Dysphaea dimidiata has since vanished, having perished when its sunny streams surrendered to a chronic obsession with clean banks that still plagues the managers of urban parks. The sole survivor of the family on the island, Euphaea impar clings to the edges of existence on the few waterways that course through the reserves without the impediment of straight and narrow plans. Here, by shaded channels flowing over leaf litter and soft, sinking silt, it is still possible to find bold relicts who guard their share of a refuge at risk of depredation and land on each new perch with the trepidation of half-opened wings.