Aulax chrysothamni, new species

Gall.--Polythalamous. White, densely covered with white felt-like substance. Elongated, rounded or club-shaped, enlargements of the terminal twigs of the branches of a species of Chrysothamnus (Bigelovia), measuring 15 to 30 mm in length and 12 to 20 mm in diameter. Sometimes two or three galls are in a row on the same branch. Internally the gall is white and of a pithy substance.

Range: Tucson, AZ

Antistrophus chrysothamni (Beutenmüller, 1908)

Nomenclature: Aulax chrysothamni Beutenmüller, 1908

Feeds on: Induces galls on Chrysothamnus Nutt. [C viscidiflorus listed as a placeholder]

Distribution: United States: Arizona

Antistrophus chrysothamni

On Chrysothamnus sp.
Stem swellings up to 20 mm. in dia. by 40 mm. long, covered with white felt-like pubescence.

Antistrophus chrysothamni
Rabbitbrush gall wasp

Host: An as-of-yet unidentified species of rabbitbrush.

Gall location: Found on the branches, sometimes with several galls on the same branch.

Description: Rounded, medium-sized galls that are 1-3 centimeters in length and containing many chambers. Externally, they are covered in dense, white, felt-like hairs. Internally, they are white and pithy.

Range: Only known from two places in Arizona: Tucson and Cave Creek.

This species has not been seen in nearly a century! It was originally described by William Beutenmüller in 1908, and since then it has been seen only once, by Lewis H. Weld in the 1920s. The exact rabbitbrush species was not known when this gall wasp was first described. Many rabbitbrush species that are found in Arizona have a large range and can be found in many nearby states, so it is possible that this gall wasp may be encountered elsewhere in the southwestern United States

Aylax chrysothamni Beutenmuller

Aulax chrysothamni

Gall. (Plate XIV, Fig. 9.) On the stems, usually at the tips, of a species of Chrysothamnus (Biqelovia). Polythalamous. White and densely covered with a white felt-like pubescence. Elongate, rounded or club-shaped, enlargements of the twigs. White and pithy inside with many scattered larval cells. Sometimes two or three galls are in a row on the same branch. Length, 15-30 mm. Diameter 12-20 mm.

Habitat. Arizona (Tucson).