Here’s an addendum to the post about Unrecognized species in Bembidiina. The map below shows the known distribution of most (but not all) of the unrecognized taxa of Bembidiina in America north of Mexico. Notably absent are some of the coastal Notaphus, as well as some widespread forms such as “Bembidion kuprianovi” which consist of multiple species but I don’t know which ones are the recognized ones and which ones are unrecognized. I should also note that the distribution of these species have not been mapped in detail; for the most part, the distributions shown below are of specimens whose DNA we have sequenced, and the full distributions of some of the species is broader.
As you can see, the vast majority of unrecognized taxa are in the west, especially in California.
Update: for comparison, here is the distribution of all species. The pattern for recognized species has some similar properties to unrecognized species in that there are many more species in the west. The primary reason that there are many recognized species in Canada (including British Columbia) but relatively few unrecognized ones is the excellent work of Lindroth (1963).