Lymaenon, Walker, 1846

Huber, John T., Read, Jennifer D. & Triapitsyn, Serguei V., 2020, Illustrated key to genera and catalogue of Mymaridae (Hymenoptera) in America north of Mexico, Zootaxa 4773 (3), pp. 1-411 : 216

LYMAENON Walker, 1846

( Figs 545–560 )

Lymaenon Walker, 1846: 49 . Type species: Lymaenon acuminatus Walker, 1846 , by subsequent designation by Gahan & Fagan, 1923: 82.

Rachistus Foerster, 1847: 203 . Type species: Ooctonus litoralis Haliday, 1833 , by subsequent designation by Gahan & Fagan, 1923: 128. De facto synonymy under Lymaenon by Huber, 2015: 41.

Rhachistus [sic]: Dalla Torre, 1898: 429. Unjustified emendation.

Oophilus Enock, 1909: 458 . Type species: Oophilus longicauda Enock, 1909 , by monotypy. De facto synonymy under Lymaenon by Huber, 2015a: 41.

Agonatocerus Girault, 1913 [149]: 276. Type species: Agonatocerus humboldti Girault, 1913 , by original designation. De facto synonymy under Lymaenon by Huber, 2015a: 41.

Gonatocerus (Gonatoceroides) Girault, 1913 [155]: 255. Type species: Gonatocerus australicus Girault, 1913 , by original designation. De facto synonymy under Lymaenon by Huber, 2015: 41.

Decarthrius Debauche, 1949: 21 . Type species: Decarthrius straeleni Debauche, 1949 , by original designation. De facto synonymy under Lymaenon by Huber, 2015a: 41.

Diagnosis. Body length 560–1770 μm. Ocellar triangle with 3 or, rarely, 4 setae between lateral ocelli ( Fig. 547 ); pronotal lobes separated by a membranous gap ( Fig. 551 ); mesothoracic spiracle much larger than propodeal spiracle ( Fig. 552 ); dorsellum strap-like, with anterior and posterior margins parallel ( Figs 551, 552 ); stigmal vein with apex truncate ( Fig. 554 ); propodeum with parallel or slightly converging submedian lines, often with spicules between them ( Fig. 551 ).

Discussion. Among the four genera in the Nearctic ( Cosmocomoidea , Gastrogonatocerus, Gonatocerus , and Lymaenon ) that share the following combination of features: tarsi 5-segmented, funicle 8-segmented, face with subantennal sulci, and parastigma with hypochaeta about midway between proximal and distal macrochaetae ( Huber 2015a), Lymaenon is superficially most similar to Gonatocerus because of its relatively narrow fore wing usually uniformly covered with microtrichia from base of parastigma to wing apex but sometimes with a clear area between parastigma + stigma and cubital line of microtrichia ( Fig. 554 ); otherwise it differs especially in mesosomal structure.

Nearctic hosts. Hemiptera : Cicadellidae , Membracidae .

Important references. Triapitsyn (2013a), Triapitsyn (2013b), and Triapitsyn et al. (2010) treated Palaearctic, Nearctic and Neotropical species, respectively.

Figures

FIGURE 545. Lymaenon sp., habitus. Canada, Ontario, Buckham’s Bay West, 45°29'36"N 76°6'38"W, v–x.2010, J. Read. Scale bar=500 μm.

FIGURES 546–550. Lymaenon spp. 546, L. pygmaeus (Girault), head, anterior; 547, L. pygmaeus (Girault), head, posterior, 548a, L. ornatus (Gahan), head, lateral; 548b, male lateral (internal) showing ocular apodeme; 549, L. sp., head, anterodorsal; 550, L. pygmaeus (Girault), antenna. antenna. Scale bars=100 μm.

FIGURES 551, 552. Lymaenon spp., mesosoma. 551, L. pygmaeus (Girault), female, dorsal; 552, L. ornatus (Gahan), male, lateral. Scale bars=100 μm.

FIGURES 553, 554. Lymaenon pygmaeus (Girault). 553, mesosoma, ventral; 554, wings. Scale bars=100 μm.

FIGURES 555–557. Lymaenon spp., metasoma. 555, L. pygmaeus (Girault), dorsal; 556, L. ornatus (Gahan), lateral; 557, L. pygmaeus (Girault), ventral. Scale bars=100 μm.

FIGURES 558–560. Lymaenon ornatus (Girault), male. 558, antenna; 559a, metasoma, dorsal; 559b, metasoma showing genitalia seen through gaster; 560; metasoma, lateral. Scale bars=100 μm.