Andricus guanajuatensis Pujade-Villar, 2013
Andricus guanajuatensis Pujade-Villar, In Pujade-Villar et
al. (2013b: 188)

Gall (Figs. 3f-h). Plurilocular, they develop on the branches, chestnut-red in color, large (2.0–6.0 x 1.0–5.0 cm) and regular. They are composed of smaller, hard, completely fused globular masses that surround the branches. The surface is light green when they are young and light gray at maturity, delicately rough and wrinkled; the network-shaped anastomosis have a color similar to that of the depressed areas and are often slightly cracked (this structure is visible under stereomicroscope magnification). The larval chambers (3.0 x 4.5 mm) are widely separated, not very numerous. The chamber walls are thick, yellowish, and very hard (2-3 mm thick). The galls remain on the branches for several years and become darker over time.

Hosts. Quercus obtusata and Q. rugosa (Quercus section); also mentioned on Quercus castanea Née, 1801 (Lobatae section) in the original description, but this data needs to be verified.

Biology. Species known only for the asexual generation. The adults emerge between September and May; in Santa Fe, emergences occurred in May.

Distribution. Cited in the states of Guanajuato and Queretaro (Pujade-Villar et al. 2013a); first record for Mexico City (Santa Fe) and first record on Q. rugosa.

- Uriel Barrera-Ruiz, Victor Cuesta-Porta, David Cibrian-Tovar, Aitor Martinez-Romero, Juli Pujade-Villar: (2021) Avispas agalladoras de los encinos de Santa Fe (Ciudad de México, México) (Hymenoptera, Cynipidae: Cynipini; Fagaceae)^©