Gynacantha membranalis is one of the larger dragonfly species in Suriname that mainly flies at dusk.
It can be recognized by its large size and dark brown patches on the wingbase.
I saw this female ovipositing in the mud of a shaded rainpool on the road just in front of the entrance to the Brownsberg accomodation.

Cornelio Andrés Bota-Sierra, a Colombian dragonfly expert who I met during my stay at Montezuma Lodge in Tatamá National Park, Colombia, in June 2015, helped me identifying this species.

Brownsberg Nature Park, Suriname, 16 October 2016