198 



WILLIAM MORTON WHEELER. 



Stenamma. Ce charactere qui m' avait echappe a son impor- 

 tance me porte a croire que les analogies frappantes entre les 

 deux genres sont dues a une adaptation convergente. Holco- 

 myrmex est la modification granivore de Monomorium, comme 

 Messor est celle de Stenamma (Aphcenogaster)." There are no 

 ammochaetae in the Asiatic species of Holcomyrmex {criniceps 

 Mayr and scabriceps Mayr of India), though the lower surface 

 of the head is abundantly pilose like the remainder of the body. 

 These species evidently inhabit rather humid regions. In the 

 species from the dry Sahara {H. chobaitti Emery and faf Forel) 

 the ammochaetae are beautifully developed. In chobauti (Fig. 7) 

 the gular bristles are very long and inserted in an arcuate series, 

 and the head is very flat, with concave gular surface. Forel 

 describes H. faf as having long red hairs on the lower surface 

 of the head. In H. lameerei Forel, which also inhabits the Sahara, 

 the gular hairs are shorter, straighter and diffuse, but neverthe- 

 less abundant. 



Subfamily Camponotin^e. 

 Myrmecocystns Wesmael. — This genus includes the only 

 prominent . and characteristic Camponotine ants common to 

 the arid regions of both hemispheres. The Old World spe- 



FlG. 8. fylyrmecocystus bicolor F. ( = M. viaticus desertorum Forel). 



cies, ranging from the plains of central Asia through central and 

 southern Europe and north Africa to Spain and Morocco, are 

 all very agile, entomophagous ants, which run rapidly over the 

 dry, sunny soil in pursuit of their food. In nearly all of these 



