REVISIOIsr OF NE ARCTIC TERMITES. 91 



their bodies to enrich the soil just as similar substances pass through 

 the bodies of the earthworms for a similar purpose. By their under- 

 ground excavations they keep the soils in a constant circulation. 



Since these termites always require access to damp earth, if this 

 source of moisture is shut off, the insects will not be able to extend 

 the galleries in wood farther and will perish. 



In the Appalachian Mountain region and in the canyons of the 

 Arizona Highlands, colonies of Reticulitermes under stones are more 

 common. 



In Arizona some species of Reticulitermes also live in the wood, roots 

 and stems of various species of cactus {Opuntia) and the dry, hard, 

 woody ribs of the giant cactus {Cereus giganteus), and in ocotillo 

 {Fouquieria splendens). 



In the prairie regions of the "Prairie Plains" and the "Great 

 Plains" areas, species of Reticulitermes occur. In Kansas these 

 termites live in large numbers in the heavily sodded prairie, feeding 

 on the roots of the vegetation. 



In Utah and Colorado, Reticulitermes infests the roots and stems 

 of sage brush and scrub oak on foothills and in canyons. In Colorado, 

 however, R. tibialis Banks is found on the mountains in the Pikes 

 Peak region at an altitude of approximately 7,000 feet. It is inter- 

 esting to note that no livmg termites were found by the writer in 

 a two-day coUectmg trip in the vicinity of the famous fossil beds 

 at Florissant, although a large fossil termite was secured which had 

 been dug out by Mr. George W. Wilson. Florissant is at an altitude 

 of 8,193 feet above sea level, m a region of low rolling hills and valleys, 

 with gravel and sand; the vegetation consists of grass, pine, aspen, 

 and occasional spruce. 



In the "Great Basin" region species of Reticulitermes are able to 

 live and survive in the dry, arid, dusty desert and foothill areas in 

 the vicinity of the Ruby Mountains, Nevada (near Elko and Lamoile), 

 by burrowing in the woody roots and stems of sage brush (Artemesia 

 tridentata) and low junipers (Juniperus, species). 



The species of Reticulitermes migrate readily; they change their 

 location within the nest, according to the season or with temporary 

 changes in temperature or moisture, and even the entire nest may be 

 moved to a new site if conditions are unfavorable. 



A single Reticulitermes colony or nest may extend into several 

 adjacent stumps, trees, or logs. 



As compared with the large-sized Termopsis, which reciuires large 

 stumps, logs, or trees, Reticulitermes can inhabit decayed wood of 

 relatively small dimensions. This is due to the fact that in the case 

 of Termopsis there are no subterranean passages, the wood only being 

 inhabited. If the reproductive forms of the first form be removed 

 from a colony of various species of Reticulitermes, the insects abandon 



