<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Andricus Hartig 1840</title> <meta content="text/html; charset=UTF-8" http-equiv="content-type"/> </head> <body> <h2> <i>Andricus</i> Hartig, 1840</h2> <p>The concepts of the gallwasp genera <i>Andricus</i> Hartig, 1840 and <i>Callirhytis</i> Foerster, 1869 are still somewhat chaotic, especially for Nearctic <i>Callirhytis</i>. According to Weld (1951, 1952a) species that have a basal lobe on their tarsal claws (toothed tarsal claw) belong to <i>Andricus</i>, while species without a basal lobe on the tarsal claws (tarsal claw simple) have been placed in <i>Callirhytis</i>. Nieves-Aldrey (1992), in his revision of the European <i>Callirhytis</i> species, showed that the sexual and asexual generations of different <i>Callirhytis</i> species vary in the presence or absence of toothed tarsal claws, and hence that this character cannot be used to distinguish these genera. Originally <i>Callirhytis</i> was erected for the European species by Foerster (1869) and the main generic diagnostic characters he proposed were the transversely striate mesoscutum and the presence of the malar sulcus. Weld (1922a,b, 1926, 1952a, 1959) included many species in <i>Callirhytis</i> and established particular species groups, but neglected the diagnostic characters of <i>Callirhytis</i> given by Foerster (1869). As a result, the Nearctic <i>Callirhytis</i> became a polyphyletic group, as has been demonstrated with multiple datasets (Nylander 2004, Liljeblad <i>et al.</i> 2008, Ronquist <i>et al</i>. 2015). Many North American species assigned to <i>Callirhytis</i> (Weld 1951, 1952a, Burks 1979) have already been transferred to the newly established genera <i>Zapatella</i>, <i>Melikaiella</i> and <i>Kokkocynips</i> (Nieves-Aldrey <i>et al</i>. 2021, Pujade-Villar <i>et al</i>. 2012a, 2014a). The tarsal claw character is equally confusing in <i>Andricus</i>. In some <i>Andricus</i> species, the male of the sexual generation has tarsal claws without a basal lobe, while in the females the basal lobe on the tarsal claws is present, for example, in the Western Palaearctic <i>A. quercusramuli</i> (Linnaeus, 1761) and the Eastern Palaearctic <i>A. mairei</i> (Kieffer, 1906) (Pujade-Villar <i>et al</i>. 2020b). Therefore, in our interpretation of <i>Andricus</i> and <i>Callirhytis</i> we have used other characters and ignored the presence/absence of the basal lobe on the tarsal claws. As a result, all of the relevant new species described herein have been placed in <i>Andricus</i>, regardless of this character. We also note that the presence/absence of a basal lobe on the tarsal claws remains a stable and important character at the species level.</p> <p>Burks (1979), in accordance with Weld’s (1951) concept of the presence (<i>Andricus</i>) or absence (<i>Callirhytis</i>) of a basal lobe on tarsal claws, assigned 88 species to <i>Andricus</i>. Dailey & Sprenger (1973a) returned one species into <i>Andricus</i>, where it had originally been described but subsequently moved from. Melika & Abrahamson (2002) moved multiple species in and out of <i>Andricus</i>, and also noted several other previously published taxonomic changes involving <i>Andricus</i> species. Since then, Pujade-Villar <i>et al</i>. (2013b) described one species from the south-western USA, Pujade-Villar <i>et al</i>. (2017b) moved two species into the re-established <i>Dros</i>, and Zimmerman (2018) reestablished <i>Trichoteras</i> for a set of <i>Andricus</i> species galling <i>Quercus</i> section <i>Protobalanus</i> oaks. A new species of <i>Andricus,</i> <i>A. notholithocarpi</i> Melika, Nicholls & Stone, 2018, was described from California (Nicholls <i>et al</i>. 2018a), joining the species <i>A. mendocinensis</i> Weld, 1957 as the only <i>Andricus</i> species not galling a <i>Quercus</i> host, instead attacking the close relative <i>Notholithocarpus</i> (previously known as <i>Lithocarpus densiflorus</i>). Most recently Melika <i>et al</i>. (2021) moved one <i>Andricus</i> species into the new genus <i>Disholandricus</i>. Hence currently 91 <i>Andricus</i> species are known from America north of Mexico, associated with five different oak sections or genera of Fagaceae (Table 1).</p> <p>Only two <i>Andricus</i> species, <i>A. quercusfoliatus</i> (Ashmead, 1881) and <i>A</i>. <i>quercuslanigera</i> (Ashmead, 1881), are known to associate with the oak section <i>Virentes</i>. Only one <i>Andricus</i> species, <i>A. projectus</i> Weld, 1952, is associated with <i>Protobalanus</i> oaks, while the species <i>A. formosalis</i> Weld, 1944, <i>A. quercusformosus</i> (Bassett, 1864) and <i>A. longipennis</i> (Ashmead, 1887) gall section <i>Lobatae</i> oaks.</p> <p>Herein we describe 16 new species of <i>Andricus</i> of which five species are associated with <i>Quercus</i> section <i>Lobatae</i>, 10 species with section <i>Quercus</i>, and one species with section <i>Virentes</i>.</p> </body> </html>