Bees, beetle, and Joe Pye weed

Our summer is starting to wind down. It's still hot in the afternoons, but the temperature drops at night; tonight it's down to 12°C (53 F). Some of the flowering plants in our garden have given up for the year. The maples are dropping their winged seeds, which are quickly snatched up by a fat little black squirrel. The slugs had gone into hiding while the nights were hot, but they're back, chomping great holes in hosta leaves and leaving trails of slime across the pathways.

We went down to our local plant nursery to see what's happening there. It's more of the same; most of the flowers are gone, shrubs are straggly and yellowing, trees are setting fruit. And workmen are everywhere, getting the place ready for Hallowe'en. (Already!)

Many of the plants are at half price, so we loaded up with perennials that will settle in this winter and be ready to go by spring; ferns, heather, lavender, evergreen sedums.

I stopped at a stand of Joe Pye weed, looking like tattered pink mop heads, and buzzing with excited bees.

So very pink, even the stems.

A big bee, sprinkled with pollen

Neat little bee

Two bees here. Some of the flowers are still in bud.

I walked the aisles, comparing the bug populations; on other plants there were wasps and flies, but all the bees were here on the Joe Pye weed. One of the staff told me that when they were moving the plants out of the building site, they put all the Joe Pye weed on a wagon together. When they hauled it to the new location, a cloud of bees followed it all the way.

On another plant, half fallen over and unlabelled, I found this tiny beetle:

4 mm. long. Probably one of the sap-feeding beetles.

I couldn't find it on BugGuide, so I've requested an ID.

UPDATE: From BugGuide, "Twenty-Spotted Lady Beetle, Psyllobora vigintimaculata, or something close." And from the comments (Upupaepops): Western Psyllobora Lady Beetle, Psyllobora borealis. Which is so close I can't really tell the difference.