This has to be one of the neatest bugs ever. It hovers over flowers sipping nectar like a hummingbird, but it looks like a giant bumble bee. It is neither bird, bee, nor fly. Rather, this oddity is a daytime-flying moth with clear wings. Sometimes called a hummingbird moth, sometimes a clearwing moth, the species occasionally seen locally has the name of a Rocky Mountain Clearwing (Hemaris thetis).
I saw this moth on lilacs three years ago and on dandelions four years ago, but I had not found it since then until a few days ago. Curiously when seen, it was foraging on exactly the same few square metres of dandelions where one was seen four years ago.
Offered without further comment are four views of a Rocky Mountain Clearwing. The final view is my favourite.