After doing Bug of the Week for so many years, it can be difficult to find something new. This week I was lucky.
Although it looks quite a bit like a sand wasp, this is a new kind of cuckoo bee. It might be Triepeolus sp. (like this one).
Look at the tongue (proboscis) that it using to suck up nectar.
We have seen another cuckoo bee in our yard before, Xeromelecta californica (previous post).
Named after cuckoo birds, cuckoo bees lay their eggs in the nests of other kinds of bees or sometimes wasps, depending on the species. They don't build their own nests and lack pollen baskets for collecting pollen. It's not a warm and fuzzy lifestyle, but that's nature for you.