202 



WILLIAM MORTON WHEELER. 



the clypeus and gula. I find that the conditions shown in Fig. 

 13, taken from one of Emery's recent papers, 1 obtain in all of 

 these species. The gular macrochsetse are arranged in an arc on 

 each side and the insertion of each bristle is marked by a black 



Fig. 13. Dorymyrmex mucronalus Emery. 



dot. In our North American forms of D. pyramicus (Fig. 14), the 

 ammochaetae are reduced to a very prominent series on the cly- 

 peus and a few short bristles, inserted in a short irregular arc on 



Dorymyrmex pyramicus Roger. 



the middle of the gula. The latter, which are all the more con- 

 spicuous because the remainder of the body is nearly destitute 

 of hairs, nevertheless represent what may be regarded as a de- 

 generate condition. 



1 "Studi sulle Formiche della P'auna Neotropica," Bull. Soc. Ent. ItaL, 

 XXXVII., 1905, Fig. 34. 



