Jučas

Cf. lit. surn. Jùčis, Jučỹs, Jùčius (see). Maybe related to Polish. Juczka (SSNO II 496). Apparently, Jùčas and so on. surn. are abbreviations of some other, most likely, baptismal name, but it is not entirely clear from which. Cf. still in Latv. Jučiņš (LAG 459).