John Lee, a Singaporian in Hong Kong is as fascinated with wasps as I am with spiders. He has identified this as Liostenogaster sp and says that they frequent areas near Nephila webs. He has an active web site where you will find bee and wasp photos and insights.
I visited my favorite spot across from Queensway Secondary School, looking for our ladies-in-black. This was the only one I found, but what a find. Her web has not yet been invaded with Argyrodes.
Then at the proper moment, an insect flew into her web and off she was, after the insect shown here (left). On the right, you can see her reach for the insect and start to wrap it with silk
She stabilizes the insect with one left and one right leg (left) and then with her palps (right).
Next she positions the insect to inject an enzyme for dissolving the insect internal stuff (left) and inject (right)- at least that is what I think is happening
Next she starts to wrap the insect with silk. Here her left rear leg is pulling down the drag line that attaches her to the center of her web (left) while the right rear leg is extruding additional silk for wrapping. On the right, you can see how her next leg continues to extrude silk from her spinneret - to be used for wrapping
Here she has the insect tethered to the primary web - seen more clearly on the right.
I am not certain what is happening here. On the left, her jaw appears closed and on the right, open
Here she appears to be actually eating
Now she is repositioning the insect using the silk sling (sounds like competition for the Singapore sling).
On the left, she is reaching for the insect, suspended from the center of her web and on the right, either removing her dinner from inside the insect or perhaps injecting additional enzyme for liquifying the insect internal material
A better view of her manipulating the insect and its silk tether to the central portion of her web.
Here I have repositioned myself to look at her ventral side. Seen on the left is the silk tether linking the insect with the center of her web - and a closer view on the right
Here she is enjoying her tethered tasty treat (left) before releasing it so that it swings freely from the center of the web.
C. Frank Starmer