Andricus mellificus Nicholls, Stone & Melika, sp. nov.

Diagnosis. The gall is very distinctive; no other species from Arizona are known to induce such a specifically shaped and coloured gall (Fig. 171).

Gall (Fig. 171). A small unilocular bud gall, reaching 4–5 mm in diameter, green at first then becoming red- purple, in an axillary bud. Gall ovoid with a flattened top and a central nipple; nectar-secreting. Also illustrated in Figure 24 of Weld (1960).

Biology. Only females are known, which induce small bud galls on Q. arizonica; Weld (1960) also lists Q. rugosa as a host. Galls mature in April, and adults emerge soon afterwards. Although only females are known, the spring phenology of this gall strongly implies that this is a sexual generation and males remain to be discovered. This species was included under the species code spAZb7 in the Nicholls et al. (2017) study of nectar secretion in oak gall wasps. This gall was collected at several sites in Arizona, with DNA data used to confirm the morphological assessment that emerged individuals were conspecific.

Distribution. USA, Arizona: Chiricahua Mountains, Sonoita

- George Melika, James Nicholls, Warren Abrahamson, Eileen Buss, Graham Stone: (2021) New species of Nearctic oak gall wasps (Hymenoptera: Cynipidae, Cynipini)^©