140 ILLINOIS ACADEMY OF SCIENCE. 



L. umbratus subsp. mixtus var. aphidicola Walsh, fairly 

 common. 



L. umbratus minutus Emery. This ant is not at all common. 

 I have never taken it in Illinois myself, and have never seen more 

 than one nest. This was one I found near Boston, Mass. It was 

 a large mound nest about two and a half feet high, and contained 

 many thousands of individuals — males, females, and workers. The 

 specimens I have from IlHnois were collected by Dr. C. C. Adams 

 from a mound nest near Chicago. 



L. (Acanthomyops) clavig.er Roger. 



L. {Acanthomyops) latipes Walsh. 



L. {Acanthomyops) interjectiis Mayr. 



These three species of the subgenus Acanthomyops are rather 

 common in Illinois. They may be distinguished from the other 

 yellow Lasii by having an odor something like that of oil of 

 citronella. 



Formica. In my own collection and that of the State Labora- 

 tory I have found fifteen species and varieties of this genus. 



F. sanguinea rubicunda Emery. Slave-making species. 



F. sangiiina subintegra Emery. Slave-making species. 



F. rufa obscuriventris Mayr. 



F. rufa obscuripes riibiginosa Emery. 



F. rufa obscuripes melanotica Emery. 



F. cxsectoidcs Forel. A very large red and black mound-build- 

 ing ant. Not so common here as in the east. 



F. ulkei Emery. Closely related to F. exsectoides; not common. 



F. pallide-fulva schaufussi Mayr. 



F. pallide-fulva schaufussi incerta Emery. 



These last two are the common, rather large, slender, yellowish 

 brown ants found in the open fields. 



F. pallide-fulva nitidiventris Emery. Darker and not quite so 

 common as the two preceding species. 



F. fusca subsericea Say. This is the common large black ant 

 which so often disfigures lawns with its nests. 



F. fusca argentata Wheeler, a less common variety. 



F. subpolita Mayr. 



F. subpolita picea Emery. 



F. cinerea neocinerea Wheeler. I have one vial of this species 

 from New Bedford, collected by G. E. Sanders. 



