FIELD BOOK OF INSECTS. 



mediates; antennal club 3- jointed, longer than remainder 



of f uniculus Pheidole. 



Workers monomorphic or polymorphic, i. e., with 

 intermediates; antennal club indistinct or shorter than 

 remainder of funiculus 17. 



17. Last three antennal joints much shorter than re- 

 mainder of funiculus and not forming a distinct club; 

 back of thorax with an impressed suture 18. 



Last three antennal joints forming a distinct club 

 nearly as long as remainder of funiculus 19. 



18. Spurs of hind tibiae comb-like Myrmica. 



Spurs of hind tibiae simple; eyes well developed; 



no keels on clypeus; workers monomorphic. .Aphcenogaster. 



19. Clypeus with a pair of ridges which usually project 

 forward in the form of teeth Monomorium. 



Clypeus of a different conformation, rarely 2-toothed; 

 postpetiole constricted behind Leptothorax (see 15). 



Monomorium pharaonis (Plate LXXXIX) is the little 

 red or yellow ant which is often abundant in our houses. 

 A native of the Old World, it is now widely distributed. 

 M. minimum is very small and jet-black. It makes small 

 crater nests in sandy places. The workers move in files, 

 visiting plants in search of honey-dew and the secretion of 

 the extrafloral nectaries. 



Solenopsis molesta. The minute, yellow workers are 

 common in open, grassy places where they may have nests 

 of their own under stones or they may tunnel the walls 

 of nests belonging to larger ants, stealing their food. 



Pheidole pilifera is a true harvesting ant, storing the cham- 

 bers of its nests with seeds, especially of grass. The huge- 

 headed soldiers undoubtedly function as seed-crushers. 



Cremastogaster lineolata (Plate LXXXIX), in several 

 varieties, is very common under stones, boards, etc. It 

 often makes paper-like partitions in its nest or over aphids 

 and coccids on plants " cow sheds." The workers, which 

 have a disagreeable odor, move about in loose files and 

 often carry the triangular gaster over the thorax with the 

 tip turned forward. 



Aplicenogaster (several species) is usually found in shady 

 woods, in rotten wood, and under stones. 



420 



