COCKROACHES AND HOUSE AXTS. 



97 



doing" this except to locate tbe nest by following tlie workers back to 

 their point of entrance. If in a wall tlie inmates may sometimes be 

 reached by injecting bisulphide of carbon or a little kerosene. If under 

 tiooring it may sometimes be possible to get at them by taking up a 

 section. Unless the colony can be readied and destroyed all other 

 measures will be of only tem^jorary avail. 



The little black ant ( Mo iiojuorium mhu/tum Mayr) (fig. 44) is not strictly 

 a house species, although frequentl}' occurring indoors, and becoming at 

 times quite as troublesome as the red ant. Its colonies usually occur 

 under stones in yards, but are frequently found in the fields, and Avill 

 be recognized from the little i)yramids of fine giains of soil which sur- 



FiG. 44. — The little black ant (Monomorium mintttum): a. female: &. same with -w-infrs: c. male; d 

 workers; t. jiupa :/, larva ; i?, egg of worker— all enlarged (original). 



round the entrances to tbe excavations. If these colonies be oi>ened 

 they will be found to contain Avorkers and usually one or more very 

 much larger gravid females. This species, when occurring in houses, 

 can often be traced to its outdoor colony, and the destruction of this 

 will prevent further trouble. 



The pavement ant of our Eastern cities {Tetramorium c(vs2)itum Linn.) 

 (fig. 45) is in Europe the common meadow ant, and is two or three times 

 larger than either of the other species referred to. It was early intro- 

 duced into this country, and, while not yet reported from the West, is 

 very common in Eastern towns, and ])articularly here in Washington. 

 It has readily accommodated itself to the conditions of urban existence, 

 21470-Xo. 4 7 



