(Note: Monroe County, Florida, includes the southwest portion of the tip of mainland Florida and the upper and lower keys. These three parts of that county are mapped separately in the "dot maps" but not in the computer-generated distribution maps, which are strictly at the county level.)
Circled numbers are the last two digits of the earliest record for that locality. Years with arrows show place and approximate date of apparently independent introductions. Thin dashed lines show limits of spread for indicated date. Heavy dashed line is the approximate general distribution in 1980.