-'^4 .L\TS. 



2. P. califuniicits. comunchc and badins. Larger than the preced- 

 ing and living in colonies of one to a few hundred individuals. They 

 nest exclusively <>r by preference in sand, and construct flat, single or 

 multiple craters from 30-60 cm. in diameter and 3-5 cm. high with 

 rounded slopes and oblique, central entrances. The workers make no 

 attempt to clear away the vegetation around the nest. 



3. I'. Inirhatns and its numerous subspecies and varieties : nwle- 

 facicns. ni(/nsns, fuscatns, inarfcnsis, niyrcsccns, etc. This is the 

 largest and most powerful of our species, the celebrated " Texan har- 

 vester " or " agricultural ant." It forms extensive colonies of several 

 hundred individuals and shows great variability in the construction of 

 its nests. In their simplest form, c. y., in nigosus, these present a bare, 

 circular disk, or area 1-2 m. in diameter, produced by cutting down and 

 removing all the vegetation around the central opening (Figs. 159 and 

 160). In other cases, e. y., in molcfacicns, the opening is at the sum- 

 mit of a conical crater of pebbles, partly or wholly covering the disk 

 and sometimes as much as 50 cm. high (Fig. 158). This crater, as 

 well as the underlying soil, to a considerable depth (5 m. according 

 to one account!) is perforated with flat chambers connected by 

 galleries. 



4. P. occidentalis, which, like barbatus, forms large colonies and 

 clears away the vegetation from great circular areas, which vary 

 from 2-5 m. in diameter. In the center of the area it always con- 

 structs an elegant gravel cone (modified crater) 60 cm. to i m. in 

 diameter and 20-30 cm. high, with an oblique, excentric opening near 

 the base and nearly always on the eastern or southern slope. The 

 cone and underlying soil, sometimes to a depth of 3 m., are riddled 

 with flat chambers, which, as in barbatus, are denser and more numer- 

 ous in the cone and more scattered and connected by longer galleries 

 in the soil (Fig. 164). 



Some years ago I published a few observations on E. imberbiculus 

 and P. subdcntatus (19026). These and the other species of the 

 first of the above groups, like all ants that form small colonies, are very 

 timid and inoffensive. Workers of imberbiculus kept in an artificial 

 nest were seen to feed their larvae on pieces of house-flies and crushed 

 seeds. 



Of the species of the second group, only one, the Florida harvester 

 ( P. badius) has come under the observation of previous authors. Mrs. 

 Mary Treat ( 1878) studied this ant in Florida, and McCook ( 1879^) 

 made a few observations on workers kept in confinement. It harvests 

 the seeds of many plants (Euphorbia, Croton, Aristida, etc. ). and stores 

 them in the flat granaries of its nests. It not only collects seeds that 



