Acanthocaudus caudacanthus (Smith)

(Figs 2, 5)

Trioxys (Acanthocaudus) caudacanthus Smith, 1944: 97 [USNM, examined]. Acanthocaudus caudacanthus: Mackauer 1960: 138 [revised combination].

Diagnosis. The mesosoma is entirely yellow in A. caudacanthus; it is yellow except the mesonotum is brown in A. bicolor, and it is mottled yellow and brown or entirely brown in A. tissoti . The metasoma is entirely yellow in A. caudacanthus; it is partially brown in A. bicolor and A. tissoti .

Distribution. Florida (Smith 1944), Washington (Pike et al. 2000), and Wisconsin (Pike et al. 2000).

Hosts. Aphis gossypii, Uroleucon (Lambersius) erigeronense, Uroleucon (Lambersius) gravicorne (Smith 1944), Uroleucon sp. ex Aster sp. and Centaurea nigrescens (Pike et al. 2000) .

Discussion. The validity of A. caudacanthus as a parasitoid of A. gossypii is questionable. It is the only record of a species of Acanthocaudus parasitizing species in a genus other than Uroleucon . It is based exclusively on a slide-mounted specimen in the USNM putatively reared from “melon aphid,” a common name used for A. gossypii, based on label data. Host remains are not associated with the specimen.