Schneider, S.A., & LaPolla, J.S. 2011 Systematics of the mealybug tribe Xenococcini (Hemiptera: Coccoidea: Pseudococcidae), with a discussion of trophobiotic associations with Acropyga Roger ants. . Systematic Entomology 36: 57-82

Notes: The mealybug tribe Xenococcini (Hemiptera: Pseudococcidae) comprises three genera, Eumyrmococcus Silvestri, Neochavesia Williams & Granara de Willink and Xenococcus Silvestri, trophobiotically associated with ants of the genus Acropyga Roger (Hymenoptera: Formicidae). Alate Acropyga queens vertically transmit trophobionts by carrying them along on the nuptial flight, a unique behaviour termed trophophoresy. Xenococcine mealybugs have never been collected without ant associates, and putatively only associate with Acropyga. Xenococcine mealybugs are characterized by the absence of dorsal ostioles, presence of distally cup-shaped circuli and a female pupal instar rather than a third feeding instar. The phylogeny of this tribe is derived for the first time using morphological data from adult females (53 characters) through Bayesian inference and maximum parsimony methods. Monophyly of the clade is strongly supported and a discussion of their taxonomy is included. The Neotropical genus Neochavesia was recovered as monophyletic. Eumyrmococcus, as previously defined, was recovered as paraphyletic, and thus two species are transferred to Xenococcus: Xenococcus kinomurai (Williams & Terayama) comb.n. and Xenococcus neoguineensis (Williams) comb.n. Two species groups are recognized within Eumyrmococcus: the Eumyrmococcus scorpioides species group, restricted to the eastern Mediterranean and Afrotropics, and the Eumyrmococcus smithii species group, restricted to the Orient and Indo-Australasia. Six new species are described: Eumyrmococcus adornocapillus sp.n. from Australia; Eumyrmococcus sarnati sp.n. from Fiji; Eumyrmococcus ordinotersus sp.n. and Xenococcus baryglobosus sp.n. from the Solomon Islands; Neochavesia cephalonodus sp.n. from French Guiana; and Neochavesia linealuma sp.n. from Guyana. The systematics and biology of the xenococcine mealybugs is discussed in the context of obligate ant symbiosis.