This male Summer Longhorn Bee Eucera , part of the Apidae group, slept in the same Cosmos bipinnatus 'Cupcakes White' blossom for several days.
I would see it sleeping there in the mornings, gone during the day, then back again in the evening.
Look at the long antennae on the bee! Hence the name.
The peak flight period for these bees is from late June to early August, but they should still be around in September.
It's very interesting that the female Summer Longhorn Bees are solitary, but the males tend to fly in groups searching for females.
The males like to sleep on flowers, such as cosmos and sunflowers, while the females sleep on bare ground or in cracks of heavier soil.