This is the first time I observed an ultra-green sweat bee Agapostemon texanus here in our garden.
In the image above it had just landed on a cosmos cupcakes white blossom.
This bee is a native to California and common throughout North America.
It is most active from late spring through fall.
Females nest in the soil, usually in bare, flat ground.
The last time I saw one of these was in the backyard of our previous home, where it was on an orange sulphur Klondike cosmos.
Yes, cosmos is one of their favored nectar plants.