Mala in se are the offences that are forbidden by the laws that are immutable: mala prohibita, such as are prohibited by laws that are not immutable. Jeremy Bentham, “Of the Influence of Time and Place in Matters of Legislation” Chapter 5 Influence of Time. <http://www.la.utexas.edu/research/poltheory/bentham/timeplace/timeplace.c05.s02.html>