A new genus and species of slug caterpillar (Lepidoptera: Limacodidae) from Taiwan Lin, Yu-Chi Braby, M. F. Hsu, Yu-Feng Zootaxa 2020 2020-07-07 4809 2 374 382 9BDKF Lin, Braby & Hsu Lin, Braby & Hsu 2020 [151,514,225,252] Insecta Limacodidae Epsteinius Animalia Lepidoptera 2 376 Arthropoda genus gen. nov.  ( Figs 1–4, 11, 13, 14, 17, 29, 30, 36, 37, 45, 46)  Typespecies.  Epsteinius translucidusLin, sp. nov.(here designated).   Diagnosis.  Epsteiniusdiffers from  Microleon( Figs 5–9, 12, 15, 16, 18, 34, 35, 43, 44; Solovyev, 2008; Sasaki, 2016; Sohn et al., 2018) by the following characters: (1) adults are smaller in size—male forewing length of  Epsteiniusis 5.3–5.5 mmcompared with 6.3–7.9 mmfor that of  Microleon; (2) in  Epsteiniusthe hindwing is narrower with the termen rounded, whereas in  Microleonit is broader with the termen distinctly angular; (3) the labial palpus of  Epsteiniusis shorter (approx. 2.0–2.5 times the diameter of the eye) than that of  Microleon(approx. 3 times the diameter of the eye); (4) in  Epsteiniusthe upperside of the forewing has the inner half dark brown with a purple iridescent suffusion, whereas in  Microleonthere are usually two large irregular orange patches, one at base and the other in the median area of dorsum, and it lacks the purple suffusion; (5) in  Epsteiniusthe scale fringe of the hindwing is grey, whereas in  Microleonit is conspicuously black at the tornus. In addition, the male genitalia of  Epsteinius( Figs 13, 14) differs from that of  Microleon( Figs 15, 16) in many characters, including the form of the gnathos which has a sharply down curved tip, the valva which has two long processes along the dorsal margin, and the phallus which is shorter and basally enlarged and rounded with two conspicuous cornuti. In contrast, the genitalia of  Microleonhas the gnathos with a T-shaped end, no process along the dorsal margin of the valva, and a relatively straight phallus without cornuti. The female genitalia of  Epsteinius( Fig. 17) differs from  Microleon( Fig. 18) in having a short and wide ductus bursae, and an ovate corpus bursae containing two signa each with a row of flat complex teeth. In  Microleon, the ductus bursae is long and coiled, and the corpus bursae is ovate, containing only one signum with a set of sharp complex processes over its surface. Although the early instar larvae of  Epsteinius( Figs 24, 25) and  Microleonspp. ( Figs 19, 20) are very similar, they diverge considerably in color pattern and shape in the final instar larvae, as follows: (1) in  Epsteinius( Figs 26, 27, 31, 32) the shape of the body is elliptical, whereas in  Microleonspp. ( Figs 21, 22) it is narrower with a humped dorsal surface; (2) in  Epsteiniusthere is usually an indistinct brown lateral patch (which varies among individuals), whereas in  Microleonspp. there is a distinct red subdorsal patch; (3) in  Epsteiniusthe body is semi-translucent, whereas in  Microleonspp. it is opaque; (4) in  Epsteiniusthe spine-bearing protuberances are similar to those of its early instars, whereas in  Microleonspp. the protuberances in the final instar diminish in size compared with its early instars.   Etymology.The generic name is named in honor of Marc E. Epstein for his enormous and longstanding contribution to the study of limacodid moths.