HYMENOPTERA 



259 



nests are made underground, and around the entrance all vegeta- 

 tion is cleared off and regular runways radiate out 



a 



FIG. 411. Western agricultural-ant, 

 or mound-building prairie ant (Pogo- 

 nomyrmex occidentalis}. (Enlarged) 



a, worker; b, queen. (After Headlee 

 and Dean) 



among the neighboring grasses, the seeds 

 the nest and furnish food. A few years ago 

 into New Orleans from Argentina, known as 

 the Argentine ant (Iridomyrmex humilis), 

 and has now spread over Louisiana and 

 neighboring states, becoming a very serious 

 household pest as well as attacking vegeta- 

 tion. Another common species of this fam- 

 ily (Solenopsis 

 geminatd) is 

 one of the 

 most impor- 

 tant enemies 

 of the larvae of 

 the cotton-boll 

 weevil. It will 

 thus be seen 

 that our com- 

 mon ants are 

 of very diverse 

 habits and of 

 varying eco- 

 nomic impor- 

 tance. They 

 are much more 

 abundant in 



of which are stored in 

 a species was imported 



FlG. 412. Solenopsis geminata 

 Fab., a native ant which is a val- 

 uable enemy of the cotton-boll 

 weevil. (Much enlarged) 



(After Hunter and Hinds, United 

 States Department of Agriculture) 



FIG. 413. Work of the 



black carpenter-ant (Cam- 



ponotiis pennsylvanicus] in 



black spruce 



The injury to the living tree 

 allowed the ants to enter, so 

 that the heartwood was com- 

 pletely destroyed by them and 

 the tree fell. (After Hopkins) 



