There's been an autumn bloom of spittlebugs on the aromatic grey leafed plants: artemisia, lavendar, rosemary. This morning I noticed the adult bugs have emerged from their wads and the branches were dotted with tiny brownish bugs. When you disturb them they jump away with a snap. I found a pair of shed exoskeletons, too. Apparently the mature nymphs crawl out of the spittle wad, attach to the substrate, and undergo the final molt.