Callirhytis balanaspis, new species

Host. — Quercus marilandica Muenchhausen.

Gall. — Produced in the fall in October on immature acorns which are about 6 mm. in diameter, the size being characteristically larger than the normal young acorns. It is deeply embedded in the acorn cup beside the acorn, less than half of the gall protruding, and secretes honeydew at apex while growing. When detached the gall is 5 by 7 mm., flattened, tapering at each end. The larval cell is in the middle and placed transversely.

Habitat. — The type material was collected at Texarkana, Arkansas, October 15, 1917. A pupa was cut out March 25, 1919 (trans- formed by April 29), and two living flies were cut out December 2, 1919. Normal emergence date unknown. The same galls were noted at Ironton, Missouri; Little Rock and Hot Springs, Arkansas; and at Palestine, Texas. Large numbers were seen at Eosslyn, Virginia, and in the District of Columbia on October 10, 1920, when the galls were dropping to the ground and being gnawed open, probably by mice.

Callirhytis balanaspis Weld (only the asexual generation is known) induces acorn galls on red oaks.

Callirhytis balanaspis

Quercus catesbaei [laevis], velutina
Acorn galls
A pip gall in fall on immature acorn, 6 mm in dia, larger than the normal young acorns.

Quercus marilandica
Acorn galls
A pip gall in fall on immature acorns 6 mm in dia and larger than normal young acorns, secreting honeydew.

[Photo caption]
On immature acorn of Q marilandica. Also on Q velutina, catesbaei [laevis]. Galls drop in early Oct. Adults emerged the second spring Apr 9 and the third spring Apr 3 (DC).

Andricus balanaspis (Weld, 1922), comb. nov., sexual generation

Synonyms: Callirhytis balanaspis Weld, 1922b: 22, female, gall.

Biology. Alternate asexual and sexual generations are known, inducing galls on red oaks in (Quercus section Lobatae). The asexual generation galls (Figs 58–60) have been found on acorns of Q. marilandica and Q. myrtifolia, mature in October, adults emerge in spring of the following year. To date, sexual catkin galls have only been recognised on Q. inopina and Q. myrtifolia, mature in April, adults emerge soon afterwards.

Distribution. USA: Washington DC, Missouri, Arkansas, Texas, Virginia, Florida.

The authors’ unpublished sequence data show that A. balanaspis is part of a clade of species galling red oaks whose sexual generations, where known, are on catkins and asexual generations, where known, are acorn galls. This clade includes species such as Callirhytis carmelensis Weld, 1922, A. cooki, C. myrtifoliae, A. fitpatricki Melika & Abrahamson, 2021 and C. balanacea Weld, 1944