Andricus nichollsi Melika & Stone, sp. nov.

Diagnosis. The gall somewhat resembles the sexual gall of Andricus kingi Bassett, 1900 but it is larger and greenish.

Gall. (Fig. 204). A small pointed unilocular leaf gall, 4–5 mm tall, 2 mm across, on edge of leaf, which causes the leaf to curve inwards at the point of gall attachment. Gall pale green with scattered brown flecks and covered with a dense coating of short hairs. Some of the hairs and the gall tip become red and then brown as the gall matures.

Biology. Only females are known. Their morphology strongly suggests that they belong to the sexual generation rather than the asexual generation. This is also suggested by the gall’s rapid development in spring. In addition, very similar galls with comparable morphology (small, unilocular, roughly conical, developing on the edge of leaves) are known from the sexual generations of some Nearctic Andricus species (see Doutt 1960, Dailey & Sprenger 1973a,b). Galls develop on Q. oblongifolia, mature in April; adults emerge soon afterwards.

Distribution. USA, Arizona, Santa Catalina Mountains

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