DISTRIBUTIONS OF THE SCORPIONS CENTRUROIDES VITTATUS (SAY) AND CENTRUROIDES HENTZI (BANKS) IN THE UNITED-STATES AND MEXICO (SCORPIONES, BUTHIDAE)

Specific locality records are presented to define the distributions of the scorpions Centruroides vittatus (Say) and C. hentzi (Banks) in No rth America. The former occurs in the Central Plains as far north as T hayer County, Nebraska; the Rio Grande and Sangre de Cristo Mountains form the western distributional boundary, and the Missouri and Mississ ippi Rivers essentially do likewise on the east. Centruroides vittatus occurs just across the latter watercourses in Holt County, Missouri, and Monroe and Randolph counties, Illinois, range extensions that prob ably can be attributed to rafting or natural alterations in the rivers ' courses. Other occurrences east of the Mississippi River, in norther n Illinois, Kentucky, Tennessee, Louisiana, Mississippi and North Caro lina, are associated with cities and are mostly far outside what we co nsider the natural range; such records are regarded as human introduct ions. One of these apparently represents a viable reproducing populati on in Rutherford County, Tennessee. Likewise, records far west of the Rio Grande, in Arizona and California, are interpreted as introduction s. Centruroides vittatus traverses the Rio Grande south of Texas and o ccurs in Chihuahua, Coahuila, Nuevo Leon, and Tamaulipas, Mexico. Cent ruroides hentzi, previously known only from Florida in the United Stat es, occurs in Mobile and Baldwin counties, Alabama, and in the souther n tier of counties in Georgia. Occurrences of C. hentzi in Durham, Car teret, and Brunswick counties, North Carolina, Charleston County, Sout h Carolina, and Harris and Muscogee counties, Georgia, are considered to represent accidental human importations, although it is also possib le that the more proximal ones are peripheral isolates.