No, these aren’t wasps - they’re moths!
Members of the moth Family Sesiidae (clearwing moths) are wasp mimics, and often incredibly good ones. The easiest way to tell them apart is by the body scales (frequently there are tufts at the tail-end of the abdomen) and thickened antennae. Clearwing moths are day-fliers and can sometimes be encountered nectaring at flowers, but rarely come to lights at night.
The mimicry affords them protection from some daytime predators. The caterpillars bore through the woody stems or roots of plants, and can sometimes be significant crop pests - a familiar one to home veggie gardeners might be the Squash Vine Borer (Melittia cucurbitae). These ones are Western Poplar Clearwing (Paranthrene robiniae), which target poplars, willows and birches throughout the west.
photo by stonebird on Flickr
(via: Peterson Field Guides)