The Veronicellidae include some of the most widespread and agriculturally damaging invasive slugs. However, they are difficult to distinguish and identify accurately based on external morphology because of their great intraspecific variability, especially in body color and pigmentation pattern. Based on the published accounts, museum collections, and recent surveys, four species had been recorded previously from the Hawaiian Islands: Diplosolenodes occidentalis, Laevicaulis alte, Sarasinula plebeia, and Veronicella cubensis; and the latter three plus an additional species, Semperula wallacei, were known from the Samoan Islands. We reexamined these identifications using external morphology, internal anatomy, and/or DNA sequences. Both L. alte and V. cubensis are present on all six of the largest Hawaiian Islands. Sarasinula plebeia, although recorded previously, was not present in the museum collections and was found in only one of our recent survey samples, on O'ahu. It may in fact never have been present in the Islands previously, the earlier records being misidentifications; or it may have been present but highly localized and was not collected and deposited in the Bishop Museum (Honolulu). Unfortunately, the single Diplosolenodes occidentalis specimen was not found in the usnm collections. Molecular analyses of specimens from American Samoa, previously identified as L. alte and S. plebeia, showed them to be primarily V. cubensis, with a few Semperula wallacei and Laevicaulis sp., and a single L. alte and S. plebeia, and all specimens sequenced from independent Samoa were S. wallacei. [ABSTRACT FROM AUTHOR]