Eruga Townes 1960

Genus Eruga Townes, 1960

Eruga Townes, 1960 in Townes & Townes 1960: 238. Type species: Eruga lineata Townes, 1960, by original designation.

References. Townes & Townes 1960: 238 [review of 3 Nearctic species (all described as new); key]. Townes & Townes 1966: 18 [catalogue; 1 species in Neotropical region; 1 species in Mexico]. Townes 1969: 105 [diagnosis]. Carlson 1979: 336 [catalogue; 3 species in North America]. Gauld 1991: 345 [description; review of 8 species from Costa Rica (all described as new); key]. Gauld et al. 1998: 122 [8 species in Costa Rica; key]. Eberhard 2013: 457 [Costa Rica; host, biology]. Sobczak et al. 2018 [1 new species from Brazil; host, biology].

The genus Eruga comprises 14 species distributed in the Nearctic (three species), Neotropical (eight species) and Afrotropical regions (three species). Seven species occur in Central America and four species are known from Mexico.

Species of the genus are koinobiont ectoparasitoids of adult spiders of the families Linyphiidae and Tetragnathidae. Larvae of two species, one in Costa Rica and one in Brazil, were found to induce the host spider to spin a modified “cocoon web” which is probably better designed to support and protect the wasps’ pupal cocoons than are the normal orbs of their hosts (Eberhard 2013; Sobczak et al. 2018).

Key to species of Eruga occurring in Mexico

1. Mesoscutum brownish orange to black with notaular region and anterolateral margin broadly yellow (Figs 24, 28)........ 2

– Mesoscutum entirely black, without whitish or yellow marks (Figs 21, 33)....................................... 3

2. Propodeum polished at least centrally. Mesosoma black with a few yellow markings (Fig. 24). Hind tibia reddish brown basally to fuscous apically. First tergite 1.5–2.0× as long as posteriorly broad (Fig. 25). Third hind tarsomere 2.4–2.8× as long as broad. Malar space about 0.8× as long as basal mandibular width.................................... 2. E. lineata Townes

– Propodeum entirely granulate, dull. Mesosoma predominantly brownish orange, propodeum black (Figs 28, 29). Hind tibia white with conspicous subbasal and apical black bands (Fig. 30). First tergite shorter, about 1.3× as long as posteriorly broad. Third hind tarsomere twice as long as broad. Malar space about 0.6× as long as basal mandibular width.. 3. E. rufa Townes

3. Malar space 1.0–1.2× as long as basal mandibular width. Hind wing with distal abscissa of CU absent or vestigial; nervellus arcuate, without distinct angulation (Fig. 21). Mesopleuron immaculately black (Fig. 21). Hind coxa 80 to 100 percent black (Fig. 21)............................................................................. 1. E. atrata Townes

– Malar space shorter, 0.6–0.8× as long as basal mandibular width. Hind wing with distal abscissa of CU present; nervellus with distinct angulation (Fig. 34). Mesopleuron black with subalar prominence yellow and anterior and posterior margins pale (Fig. 33). Hind coxa predominantly yellow, sometimes infuscate basally (Fig. 33). [First tergite 1.3–1.5× as long as posteriorly broad.].............................................................................. 4. E. straussi Gauld