Season 3 Episode 19 episode 19 Teen Wolf Season 3 Episode 19 "Letharia Vulpina" Guide 01.30.2014. @ 05:25 ShahbazMalik The spoiler guide for Teen Wolf season 3, episode 19 "Letharia Vulpina" is here, check it out below. Scott and the others try to prevent a disaster. Lydia and Allison seek out an unlikely teacher. Source: SpoilerTV What disaster will Scott try to prevent?