1967] 
Barr — Cave Carabidae 
25 
triesii and striatus, and is possibly a more generalized predator. The 
pubescens group ranges south and west from Mammoth Cave and the 
menetriesii group ranges north and east, although the two groups 
overlap broadly in Edmonson, Hart, Warren, and Barren counties 
near Mammoth Cave. The two groups are probably distantly re- 
lated because of the unusual, anterior position of the first discal seta, 
but the shape of the aedeagus and the structure of the transfer ap- 
paratus is quite different in each group. 
With these 6 rather closely related species, the Mammoth Cave 
system has the most diverse trechine fauna of any cave in North 
America. Sympatry of 2, 3, or even 4 species is not uncommon in 
certain caves of the Greenbrier Valley of West Virginia or the west- 
ern margin of the Cumberland plateau in Tennessee and Kentucky. 
Perhaps more species would be discovered in some of these other 
caves if they were subjected to the same intensive collecting that 
Mammoth Cave has enjoyed over the past 125 years. Despite this 
attention, it is worth noting that P. inexpectatus was not discovered 
in Mammoth Cave until 1957, and that P. audax has been taken only 
3 times in 85 years. 
The presence of 6 similar species in the same cave leads naturally 
to consideration of the principle of competitive exclusion, according 
to which these species should occupy different niches. From what has 
already been said about the habitat preferences of P. striatus and P , 
menetriesii — the two most closely related species — it seems clear 
that their niches quite probably overlap but include significant, 
mutually exclusive components. P. piubescens probably bears a similar 
relationship to each of these two species, since the three coexist syn- 
topically not only in Mammoth Cave but also in Diamond Caverns, 
Cave City Cave, Walnut Hill Cave, and in various other caves of 
the Pennyroyal plateau. Its relative rarity in Mammoth Cave has 
yet to be explained. Neaphaenops tellkampfii feeds heavily on the 
eggs and nymphs of the cave cricket, Hadenoecus subterraneus ( Scud- 
der), although it is not limited to this food. To its exploitation of a 
food not generally utilized by other trechines may be atributed its 
occurrence in drier upper galleries, its extraordinary abundance and 
greater size, its extensive geographical distrivution, and its sympatry 
in various parts of its range with no less than 10 species of Pseudan- 
ophthalmus. The peculiar, seasonal occurrence of P. inexpectatus 
(late winter and early spring) and P. audax (late summer), and 
their great rarity could mean that they occupy unusual, as yet un- 
suspected niches, or that they compete less successfully for the re- 
sources of the environment with the other species. 
