USAGE:

api.php?what=<search string>&where=<search field>&exact=[yes:no]

where search field is one of:

name
ethnicon_1
ethnicon_2
ethnicon_3
characterization
note
work
sub_work
note_work
passage
book
casaubon_reference
kaibel_reference
note_reference

e.g.: 

http://digitalathenaeus.org/tools/KaibelIndexScriptorum/api.php?what=PTOLEMAEVS&where=Name&exact=yes
http://digitalathenaeus.org/tools/KaibelIndexScriptorum/api.php?what=comicus&where=Characterization&exact=no