Phoebis agarithe maxima fits well, there is variation but the top photo is much the same as yours. Males and females often differ as you will know.
Florida
Type locality: USA (Fl)
http://www.butterfliesofameric...
http://www.butterfliesofameric...
Phoebis agarithe agarithe is also a contender, both being subspecies of the same species.
http://www.butterfliesofameric...
Type locality: Mexico:
http://www.butterfliesofameric...
Location is often the clue as to which subspecies it is.
It pays to check other Phoebis species for locality using 'find on this page' to search for Mexico.
http://www.butterfliesofameric...
Phoebis agarithe fisheri looks similar ..
http://www.butterfliesofameric...
Whichever, it looks like Phoebis agarithe.
I found a pdf, 4th link (that changes), "Butterflies of the state of Colima, Mexico - Yale University" but it's not opening for me. Phoebis agarithe agarithe is in the link,
https://www.google.co.uk/searc...
I found you can get the article via the arrow at the end of the web address, a cached version.
The google link doesn't always work, sometimes it will if refreshed. Search for "Phoebis agarithe agarithe Colima, Mexico"
