March, 1919] A Key to Wisconsin Ants 289 



The workers are very fond of aphid excretions and like 

 substances and for this reason are commonly found in attendance 

 upon honey dew secreting Hemipterans. 



Their nests may be found in the soil under rocks, in dead 

 wood, or under the bark of trees. The nests have a very peculiar 

 rank odor. 



The workers when in large numbers are rather courageous 

 and will sting or bite. They have a peculiar habit of carrying 

 their gasters pointing upward, which much resembles the 

 habits of Staphylinids. 



Genus Leptothorax Mayr. 

 L. acervorum subsp. canadensis Provancher. 



A small brownish species with dark gaster, having the thorax 

 faintly, but distinctly impressed at the mesoepinotal suture. 



Wheeler states that it is a rather rare boreal form, which 

 nests under bark in small colonies. 



Genus Tetramorium Mayr. 



T. guineese Fabr. 



This species is reddish yellow with the exception of the 

 gaster which is almost black. The carinal grooves extend to 

 within a short distance of the posterior corners of the head. 



Workers were collected in a greenhouse at Milwaukee, 

 Wisconsin. Their habits are similar to those of T. caespitum. 



Genus Solenopsis Westwood. 

 S. molesta Say. 



The minute workers of this species are yellow and have 

 distinct two jointed antennal clubs. 



This ant is very common to the Northern and Eastern 

 States. In Kansas it is known to attack corn and related 

 cereal crops. The workers gnaw into the kernels of the grain 

 and destroy the germinating portions, thus seriously damaging 

 the crop. Occasionally this species attacks small fruits, like 

 strawberries and raspberries and injures the fruit by eating 

 out irregular holes. 



