Terminal-instar larval systematics and biology of west European species of Ormyridae associated with insect galls (Hymenoptera, Chalcidoidea) Author Gomez, Jose F. Author Nieves, Maria Hernandez Author Gayubo, Severiano F. Author Nieves-Aldrey, Jose Luis text ZooKeys 2017 644 51 88 http://dx.doi.org/10.3897/zookeys.644.10035 journal article http://dx.doi.org/10.3897/zookeys.644.10035 1313-2970-644-51 C86EC931EA0547DA9B942386D1624FB5 Ormyrus nitidulus (Fabricius, 1804) Material examined. ex gall Andricus hispanicus on Quercus canariensis , Spain, Malaga : Algatocin , 19.VIII.02, J. L. Nieves leg (n = 1); ex gall Andricus hispanicus on Quercus faginea , Spain, Salamanca: Laguna de San Marcos, 26.VIII.03, J. L. Nieves leg (n = 1) Description. n = 2; Body length: 4.28 +/- 0.87 mm (min-max: 3.67-4.90 mm), width: 2.13 +/- 0.18 mm (min-max: 2.00-2.25 mm). The larva of this species is the largest among all the European species. Is quite similar in most diagnostic characters to the larvae of the related species Ormyrus pomaceus , being differentiated by its large size and the blister like sculpture much less conspicuous. Other diagnostic characters are as follows: body short and wide, not tapering towards the anal segment. Setae of thoracic segments shorter than 1/2 length of a thoracic segment; ratio AC/AV 0.77, the shortest among all the studied species (Table 2); anteromedial seatae of antennal area short, 0.3 as long as distance among antennae; lcs separated from cs 0.7 times the distance between cs; maxillary palps conspicuous (Figs 3E, 5E, 7E; Table 2). Biology. The species Ormyrus nitidulus is a member, with the closely allied Ormyrus pomaceus , of the parasitoid community associated with oak gall wasps ( Hymenoptera , Cynipini ). The two species were reared from more than 50 different species of cynipids associated with Quercus species in the west Palaearctic ( Askew et al. 2013 ); however, Ormyrus nitidulus is not as common and is less polyphagous than Ormyrus pomaceus . In contrast to the closely related species Ormyrus pomaceus , Ormyrus nitidulus prefers to attack the large galls of asexual generations of heteroecic species of Andricus . On the Iberian Peninsula, Ormyrus nitidulus was reared primarily from galls of Andricus hispanicus (Fig. 13D, E, and F) and the asexual generation of Andricus grossulariae . Our observations of dissected galls showed the larva of Ormyrus nitidulus was a primary ectoparasitoid of the galling inducer. In the host galls of Andricus hispanicus , the larvae always occupied the host central larval chamber, not the secondary cells occupied by inquilines.