This is the queen Weaver Ant, after she has flown and shed her wings. Oecophylla smaragdina (other names include weaver ant, green ant, and green tree ant) is a species of arboreal ant that forms colonies with multiple nests in trees.
Weaver ants of this species make nest being made of leaves stitched together using the silk produced by the ant larvae, as in this picture by Adonia Lam.
These nests are built by the workers, with leaves being woven together and secured by silk produced by the larvae. First a row of ants line up along the edge of a green leaf and, grasping a nearby leaf, pull the two leaves together, edge to edge. Other workers on the far side of the leaves, each carrying a larva in its mouth, apply the tips of the abdomens of the larvae to each leaf edge in turn. This produces a suture of fine silken threads that secures the leaves together. More leaves are attached in a similar manner to enlarge the nest.
I have written more about this interesting ant here:
https://www.wildcreatureshongkong.org/single-post/2018/05/05/The-biting-ant-with-many-names
Here is the queen with my wife's index finger nail for scale.