This is one of those land snail species that have been widely distributed by human activities. Its original homeland is believed to be southeast Asia. This particular individual was from Florida. About 3 weeks ago while visiting the Tampa area, I found a bunch of them aestivating under rocks in Fred Howard Park in Pinellas County.
What struck me as odd was that they had their apertures sealed with a hard calcareous epiphragm as opposed to a membranous one observed in eastern U.S. snails that normally don't experience long dry periods. I had always assumed that snails that built calcareous epiphragms lived only in areas with a long dry season, for example along the coasts of the Mediterranean Sea. For example, read this post for an example of a snail (Helminthoglypta dupetithouarsi) that builds calcareous epiphragms in the Mediterranean-like climate of Monterey, California. I wouldn't have expected a snail that is supposed to have originated in southeast Asia to build a similar epiphragm.
More information on B. similaris is available here.