282 The Ohio J our rial of Science [Vol. XIX, No. 5, 



Genus Lasius Fabr. 



1. Maxillary palpi with six joints Lasius s. str. 2. 



Maxillary palpi with three joints subgen. Acanthomyops 4. 



:2. Scapes and legs with erect hairs niger var. neuniger Emery. 



Scapes and legs without erect hairs 3. 



3. Body brown in color niger var. americanus Emery. 



Body yellow in color; hairs on the abdomen subdepressed 



mixtus var. aphidicola Walsh. 



4. Petiole low and blunt lalipes Walsh. 



Petiole higher and thinner 5. 



■5. Gaster with abundant long hairs claviger Roger. 



Gaster without abundant, long hairs inter jectus Mayr. 



L. niger var. americanus Emerv^ 



This species is the most abundant of all our North American 

 ants, occurring throughout the country except in the extreme 

 southern and southwestern section. It shows great adaptability 

 in its nesting habits and may be found in the damp rotten wood 

 of forests or in the gravelly soils of open fields. In the open 

 fields their nests consist of small craters. 



The workers are exceedingly fond of the sweet secretions 

 of aphids or other honey dew secreting insects and may often 

 be found in attendance upon such forms. Their relation to the 

 ■corn and cotton root louse. Aphis maid radicis, has caused this 

 species to be considered of great economic importance. Dr. 

 Forbes, of Illinois, has published some very interesting reports 

 on the habits and life economy of this species. 



Workers of Lasius americanus have been collected that were 

 heavily infested with a parasitic fungus known as Laboulbenia 

 formicarium Thaxter. 



L. niger var. neoniger Emery. 



This ant may easily be mistaken for L. americanus from 

 which it differs by the presence of erect hairs on the antennal 

 scapes and legs. 



The habits of the two species are the same. 



Workers have been observed attending A . forbesii on straw- 

 berry plants. 



L. umbratus mixtus var. aphidicola Walsh. 



This is a rather robust, yellowish brown species with sub- 

 depressed hairs on the gaster. 



Nests are constructed under stones or in the base of stumps 

 in damp shady woods. The colonies are rather large and are 

 ^iven to cultivating subterranean aphids. 



