394 



Kansas State Board of Agriculture. 



FIG. 342. External view of a nest of the mound-building prairie ant 

 (Pogonomyrmex occidentalis) . (Original.) 



Distribution. 



This ant is found throughout Kansas west of a line running across 

 the state through Belleville, in Republic county, and Oxford, in Sumner 

 county. The mounds are small and scarce in the eastern border, but 

 become larger and more plentiful westward. 



Habits and Life History. 



The ants clear away the vegetation from a small area and construct 

 their mounds near its center. (Fig. 342.) They excavate an extensive 

 series of chambers and connecting galleries that reach far down into 

 the earth, in many cases ten or more feet. Above the excavations they 

 pile the mined soil, cementing it together to form a mound ranging from 

 a few inches to two feet in height, itself honeycombed with chambers and 

 passageways. A layer from one-half to one inch in thickness over the 

 top of the mound is composed of coarse particles. The sides of the 

 mound thus constructed are pierced by from one to three or more 

 funnelshaped openings. 



The entire colony, consisting of a limited number of males and fertile 

 females (queens) and, in large nests, of an immense number of workers 

 (sterile females), lives and reproduces within these ever-dark chambers 

 and galleries. During summer, when the weather is clear, the workers 

 go into the field between eight and nine o'clock in the morning. They re- 

 turn to the nest about noon and remain there until the hottest part of 

 the day is past, then come forth and work until evening. On cloudy 

 days they do not return at noon. Just before sundown a small force of 

 workers collects little pebbles and other coarse particles like those of 

 which the gravelly roofing is composed, and stop up the openings so 

 carefully that one must look a long time to discover their location. On 

 the approach of a storm a large force is employed and the gateways are 

 closed in haste, but when it has passed they are reopened and the ants 

 return to their work. 



