Length: Males 5.0 - 11.5 mm. Females 7.0 - 15.0 mm.
Of Trichodes ornatus Linsley and MacSwain (1943) wrote that it is "the commonest and most widely distributed representative of its genus in western North America. It occurs in nearly every state west of the Rocky Mountains, as well as in British Columbia and Alberta, and ranges from sea level up to ten thousand feet elevation."
Adults are often found feeding on yarrow, on milkweeds, and on various yellow composites. While early writers stated that the adults feed only on pollen, Linsley and MacSwain stated, "Although pollen is undoubtedly a major item of food, the present writers have observed adults to completely dismember and feed on other living insects (mostly small Coleoptera) and the female to consume the male after copulation."
Larvae are parasites in bee nests (primarily of the family Megachilidae), where they feed on larval bees. If bee larvae are not available the larval beetles can develop on a diet of pollen, though in that case development may take three times as long (Linsley and MacSwain 1943).
Photo data: 30 May 2010. Red Rock Canyon, Clark County, Nevada.