220 UNIVERSITY OF COLORADO STUDIES 



Formica sanguinea Latr., subsp. rubicunda. A number of individuals found at 

 Tolland in a damp cellar had chewed the wood of shelves into a fine sawdust for their nest. 

 They are usually found with slaves. The enslaved individuals belong to other species of 

 Formica. 



Formica munda Wheeler. This species is abundant at altitudes below 7,000 feet. 

 The nests are usually in grassy places. 



Lasius niger L., var. americanus Emery. Ants of this variety occur from low to 

 high altitudes in Colorado. They often build tents low to the ground around the stems 

 of plants and like Cremastogaster lineolata, keep captive there a number of aphids or 

 coccids, chiefly mealy-bugs. In overturning a stone, under which there is a colony of 

 these ants, the workers are seen to seize the mealy-bugs and take them away out of sight. 

 In many of the middle-western states, these ants do considerable damage in corn fields, 

 by their habit of cultivating the root-aphids of the corn. 



Leptothorax spp. This is a very widespread group of small ants. They form very 

 small colonies, often not more than 25 to 50 individuals. The nests are small and may be 

 in the ground, between stones or within the tissues of plants. Abandoned galls are often 

 utilized for their nests. 



Myrmecocystus melliger mendax Wheeler. Members of this genus are confined 

 almost entirely to the warmer and arid countries. They are abundant in Colorado as far 

 north as Colorado Springs. As far as known, only one colony has been seen in northern 

 Colorado and that by Wheeler in Denver. This is the farthest point north to which any 

 of the Myrmecocysti have been traced. The Myrmecocysti or Honey Ants are interesting 

 from the fact that certain workers, "repletes," store large quantities of honey within their 

 abdomen. The size of the abdomen becomes prodigious and the individual is barely able 

 to walk. 



Myrmica rubra brevinodis Emery. In the neighborhood of Boulder, Professor 

 T. D. A. Cockerell has noticed that masses of these ants are attracted to the sunflower 

 plant and are killed by the sap which exudes from broken branches. It illustrates a case 

 of maladjustment in the relations of ants to plants. 



Pheidole ceres Wheeler. In colonies of this genus may be found four different 

 forms: large-headed soldiers, much smaller and very numerous workers, winged males and 

 winged females. Pheidole ceres is a harvesting ant which lives upon seeds stored up in the 

 nest. The nests are found in sunny places under stones. This species is rather common 

 at altitudes from 5,000 feet to 9,000 feet. 



Sympheidole elecebra Wheeler. These ants are inquiline, that is, they live with other 

 ants. They have been reported by Wheeler as occurring in the nests of Pheidole ceres, 

 which they much resemble. Unlike Pheidole, the workers are non-existent. 



Pogonomyrmex occidentalis Cresson is very abundant at elevations between 

 6,000 feet and 7,000 feet. It is called the "Agricultural" or "Mound-building Prairie 

 Ant." It is distributed over the western plains of the United States, living in large colonies 

 in gravel-covered mounds. The ants remove all the vegetation away from about the nest, 

 so that the mound stands in a cleared, circular space. These mounds, located in the center 

 of cleared, circular areas, are conspicuous objects in many parts of the great plains. 



Solenopsis molesta Say. This small, yellow species has a wide geographic range. 

 It often forms compound nests with larger ants. Living in the nests of other species, the 



