Genus: Anthidium Fabricius, 1804
Subgenus: A. (Anthidium) Fabricius, 1804
Species: Anthidium tenuiflorae Cockerell, 1907
Common name: none
Anthidium (Anthidium) tenuiflorae are dark brown to black, with light brown coloration on the tarsi, and ivory or yellow maculations (Gonzalez and Griswold 2013). Females have white or yellow pubescence except for darker hairs on the inner tarsi and center of the sternal scopa. The fore and mid basitarsi are covered by dense tomentum. Females have a body length of 8.0–9.3 mm, and males range in body length from 8.9–13.1 mm (Gonzalez and Griswold 2013).
(modified from Gonzalez and Griswold 2013)
Female A. tenuiflorae can be differentiated from other Anthidium species by the combination of pale sternal scopa, distinctly shiny terga, and T6 broadly truncate without a distinct median emargination (Gonzalez and Griswold 2013). Male A. tenuiflorae may be confused with A. emarginatum and A. platyfrons by the broadly rounded lateral lobe of T7, and S4 with an apical brush of long, black hairs. Male A. tenuiflorae can be differentiated from these two species by the narrow, acute lateral lobe of S6 with a concave outer margin and a long, narrow apical process of S8 (Gonzalez and Griswold 2013).
Anthidium tenuiflorae adults have been recorded in flight from March to September; however, a single specimen was recorded in November. Peak activity occurs from June to August (Gonzalez and Griswold 2013).
Anthidium tenuiflorae is a generalist that has been observed visiting a variety of species within Alliaceae, Asteraceae, Boraginaceae, Brassicaceae, Caryophyllaceae, Crassulaceae, Fabaceae, Lamiaceae, Onagraceae, Plantaginaceae, and Rosaceae (Gonzalez and Griswold 2013).
Anthidium tenuiflorae may nest in holes in the ground. Nest plugs are comprised of pebbles (Hicks 1926).
Anthidium tenuiflorae are thought to be the most widespread species of Anthidium in North America. They occur in the U.S. in California, Arizona, northern New Mexico, Montana, North Dakota, Minnesota, Alaska, Colorado, and Washington (Gonzalez and Griswold 2013). In Mexico, they occur in Baja California. In Canada, they are found in British Columbia, Yukon, Alberta, and Saskatchewan (Gonzalez and Griswold 2013). They are found primarily in pine-oak forests, montane chaparral, woodlands, forests, shrub steppe, grasslands, and tundras, but are absent in deserts (Gonzalez and Griswold 2013).