Nudina ankistro, Volynkin, Huang, Bolotov & Spitsyn, 2021

Volynkin, Anton V., Huang, Si-Yao, Spitsyna, Elizaveta A., Bolotov, Ivan N. & Spitsyn, Vitaly M., 2021, Three new species of the genus Nudina Staudinger, 1887 from northern Indochina (Lepidoptera: Erebidae: Arctiinae: Lithosiini), Zootaxa 4970 (3), pp. 547-557 : 550

The ankistro species-group

Diagnosis. Imagoes of the species-group differ from those of the artaxidia species-group by the longer lamellae of antennae of males and the shortly bipectinate female antennae (in the artaxidia species-group, the female antennae are serrate). The male genital capsule differs from that of the artaxidia species-group by the wide and heavily sclerotized transtilla, the robust harpe, and the unilobate ventro-distal process of valva. The aedeagus of the ankistro species-group has markedly larger distal carinal processes armed with clusters of tiny denticles, whereas in the artaxidia species-group, the carinal processes are markedly smaller and have smooth surface. The vesica of the ankistro species-group is much broader basally and longer than in the artaxidia species-group. The female genitalia of the ankistro species-group are characterized by the narrower antevaginal plate, the ductus bursae bearing an elongate ventral large sclerotized plate protruding to the posterior section of the corpus bursae and the large, broadbased appendix bursae curved distally and directed anteriorly.