There will be three butterfly lists available for in app purchasing once version 1.3 of FieldSurvey is released. Here is a description of their composition.
The North American Butterfly (2012) list is an optional purchase to add 709 North American butterflies to a survey. Each species entry includes a common name, scientific name, and a four-letter abbreviation. Included butterflies follow the 2004 Opler and Warren list for classifications and scientific names of North American butterflies (north of Mexico). FieldSurvey’s abbreviations are based on FieldSurvey's own four-letter abbreviations of butterfly English names as compiled in The NABA Checklist & English Names of North American Butterflies.
The Eastern North American Butterfly (2012) list is the same in every way except that it includes only 439 species of eastern North American butterflies. Similarly, the Western North American Butterfly (2012) lists contains 604 western North American butterflies. The Eastern and Western lists are obviously not mutually exclusive.