ANAGRUS Haliday, 1833

(Figs 86–119)

Anagrus Haliday, 1833a: 268, 1833b: 346 . Type species: Ichneumon atomus [as atomos] Linnaeus, 1767, by subsequent designation by Westwood, 1839: 78.

Pteratomus Packard, 1864: 137 . Type species: Pteratomus putnamii Packard, 1864, by monotypy. Synonymy by Girault, 1929 [428]: 27; fixed by Annecke & Doutt, 1961c: 7.

Packardiella Ashmead, 1904: 364 . Unnecessary replacement name, proposed without apparent reason (name not preoccupied) according to Gahan & Fagan, 1923: 103 and Peck, 1963: 896.

Paranagrus Perkins, 1905: 199 . Type species: Paranagrus optabilis Perkins, 1905, by original designation. Synonymy implied by Bakkendorf, 1926: 258; fixed by Annecke & Doutt, 1961c: 7.

Anagrella Bakkendorf, 1962: 372 . Type species: Anagrella mymaricornis Bakkendorf, 1962, by monotypy. Synonymy by Viggiani, 1970: 139.

Diagnosis. Body length 300–800 μm. Face without subantennal sulci (Fig. 87); ocelli usually (except subgenus Anagrella) delimited by stemmaticum (Fig. 107); clava 1-segmented (entire), in lateral view often clearly asymmetrical, with dorsal margin usually strongly curved and ventral margin almost straight (Figs 86, 89, 98, 100); mandible with 3 teeth (Fig. 109); frenum longitudinally divided by narrow or wide sulcus into two lobes, each lobe shorter than wide (Figs 90, 102, 103, 110, 114).

Discussion. Four other genera in the Nearctic have a longitudinally divided frenum: Krokella, Platystethynium (Platypatasson), Schizophragma and Stethynium; Omyomymar may have an incompletely divided frenum. Females of all of them differ from Anagrus females by having the clava 2- or 3-segmented.

Considerable literature exists on various species of Anagrus because of their actual or potential use as biological control agents of economically important insects. Older references to various species of Anagrus may well be based on completely or partly incorrect identifications, e.g., specimens identified as A. armatus before Chiappini et al. (1996) and Triapitsyn (1998, 2014c). The older references are cited under the presumed correct name where this could be determined to complete the titles and journal references, mostly those in Peck (1963) or Burks (1979). Three subgenera, A. ( Anagrus), A. ( Anagrella) and A. ( Paranagrus), are currently recognized.

Nearctic hosts. Hemiptera: Cercopidae, Cicadellidae, Cixiidae, Delphacidae, Miridae, Tingidae . Odonata: Coenagrionidae, Lestidae .

Important references. Gordh & Dunbar (1977) keyed the Nearctic species, Chiappini et al. (1996) treated the Holarctic fauna, Triapitsyn (1997, 2002a) reviewed the species in America south of the United States, Triapitsyn & Beardsley (2000) treated the species of the Hawaiian Islands, Triapitsyn (2001) reviewed the species in the Australasian region, Triapitsyn (2015b) gave an annotated key and catalogue to the world fauna, and Chiappini & Lin (1998) and Li et al. (2018) keyed the species of China.