No. 22.] HYMENOPTERA OF CONNECTICUT. 583 



16. Thorax and petiole without any traces of teeth or spines; pro- 



notum never angular 17 



Epinotum armed with spines or teeth 18 



17. Petiole distinctly pedunculate Monomorium p. 584 



Petiole not pedunculate Xenomyrmex 



18. Mesoepinotal constriction distinct; males ergatomorphic 



Symmyrmica 

 Mesoepinotal constriction faint or lacking; males not ergato- 

 morphic Lepthothorax p. 588 



19. Workers strongly dimorphic, usually without intermediates 



connecting the extreme forms; antennal club 3-jointed, 



longer than remainder of funiculus Pheidole p. 584 



Workers monomorphic or polymorphic, *. e., with mediae in- 

 termediate between major and minor forms; antennal club 

 indistinct or shorter than remainder of funiculus 20 



20. Last three antennal joints much shorter than remainder of 



funiculus and not forming a distinct club 21 



Last three antennal joints forming a distinct club nearly as 

 long as remainder of funiculus 26 



21. Thoracic dorsum impressed at mesoepinotal suture; promeso- 



notal suture usually distinct 22 



Thoracic dorsum without any traces of suture or impressions 



Pogonomyrmex 



22. Posterior tibial spurs pectinated Myrmica p. 587 



Posterior tibial spurs simple 23 



23. Small hypogaeic species, with vestigial eyes and two keels on 



clypeus Stenamma p. 585 



Medium-sized epigaeic species with well-developed eyes and 

 no keels on clypeus 24 



24. Workers monomorphic 25 



Workers polymorphic Novomessor 



25. Cosmopolitan species with moderately slender thorax and 



legs Aphaenogaster (s. str.) p. 585 



Tropical and subtropical species with very slender thorax 

 and legs Aphaenogaster (Deromyrma) 



26. Clypeus armed with a pair of ridges which project forward 



in the form of teeth, rarely without teeth, but then the 

 epinotum quite unarmed; mesoepinotal suture marked 



Monomorium p. 584 

 Clypeus of a different conformation, rarely 2-toothed, but 

 then the mesoepinotal suture indistinct 27 



27. Postpetiole campanulate, not constricted behind, but applied 



with its whole posterior surface to first gastric segment 



Macromischa 

 Postpetiole constricted behind . . . . . Leptothorax p. 588 



