On Tradescantia leaf. I assume that these are cocoons, but I have no idea of what. It rained hard the night before and they seem to be wet.
Update: According to a National Geographic video
some parasitic wasps induce the dying caterpillar host to spin a wrapping around the wasps cocoons instead of building its own cocoon. Another gruesome example of parasitic mind control. This explains the webbing around the little cocoons.