1978] Peck — Adelopsis in the Southern Appalachians 379 
“explosive” species production on islands in 10 million years or less. 
However, the fossil record shows that other groups with the same 
Appalachian-Mexican disjunction have undergone very little dif- 
ferentation in the same time, especially in certain tree genera 
(Axelrod, 1960, p. 269; Rosen, 1978). It should also be noted that 
these papers deal more with examples that seem to be northern in 
origin and which have moved into Mexico and southwards rather 
than the opposite (Graham, 1973). 
It might at first seem puzzling that a Neotropical genus, charac- 
teristic of lowland mesic tropical forests should have species isolated 
on the highest peaks of the southern Appalachians. However, it is 
not difficult to see the origin of the situation. When they were first 
colonized the Appalachians seem to have had a tropical or sub- 
tropical climate, and to have had a more gentle relief, sometimes 
called the “Schooley Peneplain”. Their present relief is due to later 
Tertiary uplift and erosional rejuvenation, a process to which the 
beetles could undoubtedly adapt as their populations either were 
slowly elevated, or slowly moved into higher sites. 
The broad patterns of species distribution seem similar to those of 
other flightless beetles inhabiting deep litter and/or soil in the 
Appalachians (see Darlington, 1943). Close comparisons can be 
made with the eyeless Anillinus carabids (Barr, 1969; pers. comm.), 
Arianops pselaphids (Barr, 1974), and more distant ones with 
Trechus carabids (Barr, 1962, 1969), and Catopocerus leiodids 
(Peck, 1974). These show species to be generally confined to upland 
areas or in deeper soil (collected in caves) or protected gorges in the 
lowlands. Some of these groups have species which may be more 
widespread in the northern end of the unglaciated Appalachians, 
but most contain more species, but with not much more sympatry, 
in the vicinity of the junction of North and South Carolina and 
Georgia (the vicinity of Highlands, North Carolina). The mechanism 
that acted to generate and then preserve the diversity near Highlands 
might have worked in a relatively similar manner on these and many 
other groups of forest litter-inhabiting insects and other arthropods. 
Conclusion 
The genus Adelopsis , otherwise Neotropical in distribution, is 
found to have 16 species in the southern part of the Appalachian 
region of the United States. All these species are small-eyed and 
