Revision of Trechus 
49 
low, wet cliffs near the summit. It coexists with four other Trechus species 
(T. schwarzi scopulosus, T. mitchellensis, T. hydropicus beutenmuellen, T. van- 
dykei vandykei ), but is easily distinguished by the large size. The apparent 
rarity is probably real but could possibly reflect the comparatively inac- 
cessible microhabitat in which it occurs. 
Trechus (Trechus) roamcus Barr 
Fig- 2 
Barr 1962:73. Type locality, Roan Mountain, Carter County, Tennessee; 
type deposited in USNM. 
Trechus roanicus is known only from the type locality, where it occurs on 
Roan High Bluff, the highest point on Roan Mountain (elevation 6313 
feet) (1924 m). It is closely similar to T. hydropicus , but is larger (3. 8-4. 4 
mm) and coexists with the smaller and much more abundant T. h. 
beutenmuellen. The species occurs under moss carpets on north-facing 
cliffs, in contrast to T. h. beutenmuellen , which is found not only in the same 
microhabitat but also under wood chips, under moss on logs, and under 
stones near seeps. 
Subgenus Microtrechus Jeannel 
vandykei group 
Trechus ( Microtrechus ) vandykei vandykei (Jeannel), new status 
Figs. 6, 25 
Microtrechus Vandykei Jeannel 1927: 587, Figs. 1280-1285; 1931: 443. Type 
locality, Black Mountains, North Carolina; type deposited in MNP 
(not seen). 
Trechus ( Microtrechus ) vandykei: Barr 1962:77 (in part). 
Although geographic variation among the smaller beetles of the vandykei 
group was previously noted (Barr 1962: 78), I separated out only the dis- 
tinctive Smoky Mountains endemic, T. bowlingi, and incorrectly lumped 
the remainder into T. vandykei. Further study of older collections and 
much fresh material suggests that populations of the Great Balsams, 
Pisgah Ledge, and Cowee Mountains differ (at least) subspecifically from 
T. vandykei populations north of the French Broad valley, and that the 
populations of (a) the Tusquitee/Valley River, Snowbird, and Cheoah 
mountains and (b) the Unicoi Mountains, respectively, are best treated as 
distinct species. 
From T. bowlingi and T. tusquitee, which have very obtuse hind angles 
on the pronotum, T. vandykei (s. lat.) is distinguished by the briefly but 
