AMMOCH^T\E. I9I 



ant merely raises one of her fore feet, grasps the scape or funicu- 

 lus of the antenna of the same side between the strigil and the 

 curved base of the metatarsus, passes the opposed combs along the 

 apical portion of the appendage and again places her foot on the 

 ground. Very often, however, the foot is carried forward 

 directly from the antenna, thrust between the partially opened 

 mandibles and then drawn back across the teeth, along the 

 lower surface of the mandible and between the maxilla and labium. 

 The maxilla is furnished with a comb very much like that on the 

 strigil. 1 



This motion, of course, removes much of the dirt that may 

 have been collected from the surface of the antenna, since the 

 strigil and the fore tarsus are drawn through the clypeal macro- 

 chaetse, across the mandibular teeth, along the mandibular ma- 

 crochaetse and over the maxillary comb. The function of the 

 gular macrochsetae is not, at first sight, so apparent. Occasion- 

 ally, however, I have seen an ant, while thrusting her fore foot 

 forward, enclose between the strigil and metatarsus one or more 

 of the long gular hairs, and draw them through the combs or 

 along the notch between the insertions of the strigil and meta- 

 tarsus. This observation, coupled with the fact that these hairs 

 are very long, slender and directed forward, makes it highly 

 probable that they are used for cleaning the strigil, much as we 

 would use threads in cleaning a comb. In ants like the Old 

 World species of Myrmecocystus (Figs. 8 and 9) which possess 

 long mental but very poorly developed gular macrochaetae, the 

 former probably answer the same purpose. The advantage to 

 xerophilous ants of possessing a number of macrochaetal brushes 

 in addition to the strigils is obvious when we stop to consider 

 that these insects live in dry soil, which, during long seasons of 

 the year, is in a very friable and dusty condition. Both while 

 traversing the surface in search of food and while carrying on 

 their excavations, these ants are liable to become coated with 

 •dust or sand. Under such conditions the strigil must often be- 

 come clogged with earthy particles or sand grains, and an 

 apparatus for cleaning it, such as the gular and mental macro- 



1 See Janet's figures of the mouthparts of Myrmica rubra in his paper entitled : 

 " Observations suf les Fourmis," Limoges, 1904, pp. 18 and 19. 



