THE HARVESTING ANTS. 



2 73 



and of two species of Holcomyrmex (H. lameerci and chobauti) pecu- 

 liar to the sandy and extremely barren portions of the desert. H. 

 chobanti resembles .17. caviccps in having a pronounced cavity on the 

 under side of the head. Of the former species he says: "I saw the 

 long files of workers carrying seeds of the ' drin ' (Aristida pungcns) 

 to their nests. The seed of this plant has the form of a slender 

 spindle surmounted by a long, trifid and plumose spine. The ant rides 

 this grain as a witch rides her broom ; she carries it beneath her, hold- 

 ing it firmly by the small end in her mandibles with the end of the 

 grain fitting into the notch under her head. This interesting character, 

 which this ant shares with M. caviccps, may be regarded as an adapta- 





FIG. 155. Dealated female, male, and workers of Iscluwinyrmc.r cockcrclli, X 2. 



(Original. ) 



tion to the method of carrying the drin seed. It should be noted that 

 I found M. ca-viccf>s in a region of the Eolian desert where the drin is 

 almost the only plant that can subsist. On the other hand there is no 

 drin in the region of Hamada where I first found H. lamccrci, which 

 has the under side of the head but little excavated." 



Still another interesting ant of the North African desert has been 

 recently discovered in Tunis by Santschi. This is a small black species, 

 Oxyopomyrmex santschn. Its habits are described as follows by its 

 discoverer in a letter published by Forel (19040) : The nests are "so 

 characteristic that when one has once seen one of them, nothing is 



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