@e selecor with type filter specified as Monster or Mob fails

Executing commands like: /tp @e[type=Monster] ~ ~1 ~ or /tp @e[type=Mob]= ~ ~1 ~ results in the error message "Entity type 'Monster/Mob' is invalid"

I do see these entity types (Monster/Mob) in calls to addClass in the static constructor of EntityList.java, but perhaps these entity types are unsupported rather than a bug?