You wait an hour for a bus and then two turn up within the same minute...
Yes Guy. The Pearl-Bordered Fritillary was called the April Fritillary back in the early 1700's, but in September 1752 the Gregorian calendar was adopted in Britain (that year, the date actually went from Wednesday 2nd September to Thursday 14th September literally overnight!). Those missing days led (amongst other things) to the realisation that the butterfly rarely hatched out in April anymore, so the name was deemed no longer accurate.
NB: Many University May balls are still held in "May Week", which is now two weeks into June
Over to you Guy.
Trev