These are images of a male Chimney Bee in a Lance-leaf Globe Mallow flower. His wing patterns seem to be a close match to those of the Diadasia Coquillettapis subgenus grouping. Furthermore, after comparing his abdominal tip to the larger-sized male bees of that grouping, like those on the males of D. bituberculata, I can see that they are almost the same exact shape proportionally, though very different in coloration. (much, much lighter, with two darkened tips)

This bee appears to be very similar to many of the smaller sized and shorter haired male bees in the Mallow-visiting group of subgenus Coquilletapis.
The USDA Forest Service lists D. diminuta as a Globe Mallow Bee for it's common name. Please note that many other types of bees may also visit this plant. Here is the link: USDA Forest Service - Globe Mallow Bees