36 THE ARGENTINE ANT. 



In February, 1908, the senior author constructed, on the grounds 

 of the Louisiana Experiment Station at Baton Rouge, a small build- 

 ing for the purpose of studying this ant more in detail. The building 

 was 10 by 30 feet and equipped with benches having upon them gal- 

 vanized iron trays 2^ by 12 feet, 4 inches deep. In these trays the 

 cages were placed and by means of suitable connections running 

 water 2 inches in depth was kept passing through the trays day and 

 night. As the' ants would not voluntarily enter running water this 

 arrangement worked admirably. The interior arrangement of this 

 building is shown in Plate III. The iron trays and ant cages are 

 shown upon the right, with work tables, chemicals, etc., on the left. 

 The buikUng was equipped with electric and extension lights for 

 night examinations, and a combined thermograph and hygrograph 

 recorded the temperature and humidity of the room at all times. 

 For convenience this building was referred to as the ''formicarium. " 

 Plenty of windows insured full ventilation at all seasons, and to avoid 

 abnormally high temperature in summer a second or accessory roof 

 was placed two feet above the main roof. This laboratory also 

 proved a convenient insectary for the rearing of other insects. 



The Argentine ant possesses a marked proclivity for attacking all 

 insects which one has under observation, and all rearing experiments in 

 cages, no matter what the insect, must be protected from the ants. 

 The trays of running water therefore served to keep the ants away 

 from general cage experiments as weU as to confine them to the cages 

 in which they themselves were being studied. 



ESTABLISHING COLONIES FOR STUDY. 



To establish a colony in one of the artificial formicaries or cages is 

 comparatively easy. It is only necessary to secure a fertile queen 

 from some thrivuig outdoor colony and place her on the stand, first 

 placed in water, together with any desired number of workers which 

 have been captured by attractmg them to a sweetened sponge or 

 piece of fresh meat. Any lot of workers will accept any queen and 

 vice versa. When queen and workers are thus placed ui)on the cage 

 and its stand, they usually, after a few hours, take up their abode 

 in the nest proper. At firet we experienced some difficulty in pre- 

 venting them from coUectmg beneath the stand, but it was presently 

 found that if a little dii't were removed from another colony and placed 

 in the entrance of the new formicary the ants would enter at once and 

 ado])t it as a suitable home. After the establishment of such colonies 

 the queen usually commences q^^ deposition in from 6 to 48 hours. 



By establisliing colonies m this manner, witnout immature stages 

 pr(^sent, it is easy to observe the daUy rate of q^^^ deposition, the 

 incubation period of the eggs, and the duration of the larval and pupal 



