342 Bulletin American Museum of Natural History. [Vol. XXII, 



As I have shown in a former paper^ this ant occurs in populous colo- 

 nies and moves about in files in search of insect foot and the sweet 

 excretions of plant-lice. It appears to be more definitely associated 

 with pine trees than the typical apiciilatum. 



17. Dorymyrmex pyramicus Roger. — This ant, the only species 

 found over the whole cafion wall from the rim to the river, constructs 

 crater nests somewhat larger than those of Lasius niger. It is common 

 throughout Mexico, the West Indies and the southern and south- 

 western Stares, ranging as far north as New Jersey and Illinois. The 

 form occurring in the Grand Canon is somewhat smaller and paler 

 than the var. nigcr Pergande and hence approaches very nearly the 

 typical form of the species. 



A clearly marked variety which may be called bicolor var. nov. 

 has the head, thorax and petiole of the worker and female red, the 

 gaster black. It occurs in pure sand from central Texas to the Mojave 

 Desert of California and will probably be found in the lower reaches of 

 the Grand Canon. I have taken specimens of this variety at New 

 Braunfels and Elgin, Texas, Phoenix, Tucson and Yucca, Arizona, and 

 at Needles, California. It has also been taken at San Pedro, Cali- 

 fornia, by Prof. T. D. A. Cockerell, and at Tuxpan, Jalisco, Mexico, 

 by J. F. McClendon. 



x8. Iridomyrmex analis Andre. — -Many populous colonies of this 

 ant, teeming with larvae and nude pupae, were found under stones in 

 the Indian Garden and down the canon to a level of about 3000 feet, 

 but the species was not seen on the rim or at the bottom. 



19. Tapinoma sessile Say. — The common dark form of this widely 

 distributed species is rather common under stones on the Kohonino 

 Plateau. It occurs in similar localities at the same or even much 

 greater elevations in Colorado and New Mexico. I have taken it at 

 Cripple Creek, Colorado, at an altitude of 10,500 feet. In the north- 

 eastern States it descends to sea-level. 



Subfamily Camponotin.^. 



20. Prenolepis guatemalensis Forel. — A number of workers 

 assignable to this species, were taken in the sand under stones in a 

 creek bottom near the river along the lowermost portion of the Bright 

 Angel Trail. 



21. Prenolepis (Nylanderia) imparls Say. — -A form of this species 

 almost as light as var. testacea Emery, was common under stones in 



'The North American Ants of the Genus Liometopum. Bull. Am. Mus. Nat. Hist., XXI, 

 iQos, pp. 321-333. 3 figs. 



