1956] 
Wheeler and Wheeler — Veromessor 
141 
coveted Veromessor. If moisture conditions improve, we 
plan to resume our search next summer. 
The Locality 
Billings County, North Dakota. T. 140 N., R. 102 W., 
sec. 1. On an ordinary map it can be located four miles 
north-northeast of Medora, in Roosevelt National Memorial 
Park (South Unit). The site is in the heart of the Little 
Missouri Badlands. June 12, 1954. Collected by G. C. and 
J. Wheeler, No. 556. Altitude approximately 2500 feet 
above sea level. 
Habitat 
The nest was discovered in a tributary valley entering 
the valley of the Little Missouri River from the east. This 
tributary valley is short, narrow, steep-walled and about 
200 feet deep at the mouth. At the bottom is a small 
intermittent stream with little or no flood plain. The soil 
is a sandy silty loam. 
The south wall of the tributary valley is densely covered 
with a thicket of Rocky Mountain red cedar ( Juniperus 
scopulorum Sarg.). The thicket floor is covered with duff 
and moss and is relatively humid. 
In marked contrast, the nearby north wall — as the 
result of greater insolation — is treeless and sparsely beset 
with grass and low shrubs, such as sagebrush ( Artemisia 
frigida Willd. and A. tridentata Nutt.), saltbushes {Atrip- 
lex spp.) and rabbitbrush (Chrysothamnus graveolens 
Nutt.). Yucca {Yucca glauca Nutt.) and prickly pear 
{Opuntia polycantha Haw.) are present but very scarce. 
The most abundant and conspicuous ant is the western 
harvester {Pogonomyrmex occidentalis) . Scorpions {V e- 
jovis boreus Girard) are common under rocks. 
Our colony of V eromessor lobognathus was found under 
a rock halfway up the north wall. Its occurrence on a 
slope with southern exposure is significant in interpreting 
the distribution of this species, i.e., why a southwestern 
species occurs so far to the north. “The Upper Austral 
Zone, the Upper Sonoran, or semiarid subdivision of 
which penetrates only into the warmest corners of the 
