Acanthocaudus Smith

(Figs 1–7)

Acanthocaudus Smith 1944: 96 [as subgenus of Trioxys Haliday]. Type species: Trioxys (Acanthocaudus) tissoti Smith [by original designation; USNM, examined].

Acanthocaudus: Mackauer 1960: 138 [status revised to genus].

Diagnosis. Acanthocaudus can be differentiated from other genera of Aphidiinae with species in the Nearctic Region using data in the key to New World genera of Aphidiinae in van Achterberg (1997): forewing without marginal and submarginal cells, tergum 1 and sternum 1 fused basally at least to level of spiracles, hypopygium of female with prongs, hypopygium of female with accessory prongs at base of hypopygial prongs, and female with at least terga 6–7 with subapical row of pegs or spines.

Distribution. CANADA: British Columbia (Schlinger & Hall 1960); CUBA: Guantánamo (as Oriente), Pinar del Río (Starý 1981); USA: Florida (Smith 1944), Indiana *, South Dakota (Assefa et al. 2015), Wisconsin (Smith 1944), and Washington (Pike et al. 2000).

Hosts. Aphis gossypii Glover, Uroleucon (Uroleucon) ambrosiae, Uroleucon bradburyi (Olive) *, Uroleucon (Lambersius) erigeronense, Uroleucon (Lambersius) gravicorne, Uroleucon (Uroleucon) rudbeckiae, and Uroleucon (Uroleucon) russellae (see host sections for each species below for references to rearing records).