I notice that Wheelock’s vocabulary entries differ from entries in my Naw Cassell’s Latin Dictionary (F & W 1968). For example, Wheelock supplies the entry fugiO, fugere, fUgI, fugitUrum, whereas F & W lists the fourth principle part as being ‘fugitum’. What are the morphological differences? Is Wheelock drawing on later Latin, and F & W merely on the classical authors it cites below its entries?
Wow, this has been here a long time with no reply. Sorry about that (if you are still here).
Wheelock shows the future active participle because the normal 4th principal part, the perfect passive participle, is not in use (due to the intransitive nature of the verb). The future active participle, however, is in use, so it is more useful to the reader to know the supine stem after all, rather than to just leave it without a 4th principal part. F&W and many other references are a little bit misleading by showing you the unused perfect passive participle for certain verbs like this, but their intention is just to give you the supine stem for the construction of future active participles and impersonal passives.