This is a busy little bee doing his job and pollinating a Los Angeles Gilia, also know as Chaparral Gilia and Angel’s Gilia. It was growing along Santiago Canyon Road near Jamboree. According to my extensive research plus Google Translate, the Gilia family is named for Filippo Luigi Gilli, a Vatican astronomer and botanist who collected indigenous plants of North America and created a garden known as Orto Vaticano Indico at the foot of the Janiculum in Rome. He even wrote a book about it. Apparently there were a whole book’s worth of problems trying to get American plants to grow in Rome.
UPDATE: That’s no bee, it’s a hoverfly! Thanks, @Harry04945324.