No. i.] A STUDY OF SOME TEXAN PONERIXAE. II 



In digging a gallery P. Jiarpax first uses its feet and power- 

 ful mandibles in removing the earth, after the manner of the 

 digger-wasps, but as soon as the gallery is sunk to a certain 

 depth, only the jaws are used in removing the lumps of earth. 



Emery's observations 1 show that the Ponerinae have the 

 power of stridulating. He has even been able to produce the 

 sound in preserved specimens of certain American species, 

 including species of Pachycondyla. Although the ants ob- 

 served by me occasionally moved their abdomens as if stridu- 

 lating, no sound could be detected. 



The sting of the three species of Ponerinae, although of 

 formidable length, does not inflict severe pain, at least when 

 compared with the sting of the agricultural ant (Pogonomyrmex 

 barbatus Sm.). The pain may be acute for ten or fifteen 

 minutes, but then disappears, often without even reddening the 

 skin ; whereas the sting of Pogonomyrmex produces a throb- 

 bing pain which endures for hours and is sometimes accom- 

 panied by a sensation of sickness. 



The Ponerinae do not seem to feed one another, like the 

 specialized ants. In captivity P. harpax would eat the yolk 

 of egg or even sugar, but it would not eat termites. L. elon- 

 gata devoured termites and small caterpillars with avidity, 

 but would not eat flies. O. haematodes is more omnivorous ; 

 besides caterpillars, house-flies, beetles, and small Hemiptera, 

 it will eat sugar, bread, cake, etc. 



Pachycondyla and Leptogenys are like other ants in their 

 methods of killing their prey or in feeding upon it, but Odon- 

 tomachus is most exceptional in these particulars. Its whole 

 life, apart from the care of its young, appears to center in its 

 peculiarly constructed mouth. The long linear mandibles with 

 hook-shaped dentate tips are inserted close together. They 

 are usually carried wide open, as represented in Fig. I, while 

 the ant is moving about in search of food or while it is feed- 

 ing. The cutting edges of the mandibles are furnished with 

 some sensory hairs, two of which, nearly as long as the mandi- 

 bles, are inserted near the base and point directly forward 



1 Emery, C., " Zirpende und springende Ameisen," Biol. Centralbl. Bd. xiii, 

 pp. 189-190. 1893. 



