Dewdrop Spider, Argyrodes elevatus, family Theridiidae.

The Argyrodes spiders are kleptoparasites; ie, they steal small insects from the webs of other spiders. Sometimes they
share a meal with their hosts by feasting on partially digested, wrapped-up, prey. In this series of eight shots taken
over a 15-minute period, a male and female pair are seen mating in the web of a Long-jawed Orbweaver.

This is a female -- the male is the one with "boxing gloves" (palps).