TTIE ARCENTINE ANT. • 57 



GENERAL OBSERVATIONS. 



AVERSION TO LIGHT. 



The ants demonstrate in many ways their dislike of light, or at 

 least their aversion to it. Their nests are always located in dark 

 places, the ants are active all night, and their immature stages are never 

 exposed to light except for brief periods in emergencies. If the 

 opaque cover is removed from the top of an artificial ant nest for a 

 considerable time, all the ants will come out and will refuse to return 

 until the cover is replaced. Several experiments were made at 

 Baton Rouge, La., in 1909, using different colored glasses for cage 

 covers, but the ants were not satisfied unless the cover was absolutely 

 opaque. While they will go anywhere into daylight in search of 

 food, they will cover over as thoroughly as possible, with their 

 protective "sheds," the colonies of scale insects, mealy-bugs, and 

 aphides which they habitually frequent. 



SENSE OF SMELL. 



The workers exhibit a very keen sense of smell by the manner 

 in wdiich they locate certain foods. Meat which is wrapped in heavy 

 wrapping paper will attract thousands of the insects, and they will 

 work their way through the various folds and crevices of the paper 

 in a surprising manner until they reach the meat itself. The workers 

 readily secure entrance into the ordinary Mason or glass fruit jar, 

 if one omits placing beneath the cover the rubber ring or gasket. 

 No matter how tightly the cover is screwed on, the workers follow 

 the spiral threading between cover and glass until the interior is 

 reached. 



Another illustration of the sense of smell is seen in the readiness 

 with which trails are restored when broken or disturbed. If a line 

 of ants be moving across a floor in a circuitous line, for example, 

 and all ants be swept from the floor with a broom, the next on-coming 

 workers will follow exactly the original course. This may be repeated 

 indefinitely and the trail will always be established in the original 

 location. If, however, some strong-smelling substance, like oil of 

 citronella or kerosene, be placed upon the trail the ants become 

 confused at once and by their aimless wandering about show plainly 

 that they can not locate the original pathway. 



While the Argentine ants are extremely sensitive to light, it is 

 doubtful if they possess the sense of sight. The action of light can 

 generally be described as exerting a repelling influence upon them 

 and they avoid it as much as they can. That they do not use eyesight 

 in locating food substances has long been recognized. Their trails 



