180 JOURXAI. OF KCOXOMIC KNTOMOI.OGY [Vol. 2 



l);i.s.sin.i;- tlirouoh the trMvs day riiid night. As the ants will not vol- 

 untarily enter nmning water this method has worked admirably. 

 The bnildiny in whieli this work is carried on is shown in Plate 6. 

 Tlie iron trays and ant cages are shown upon the right, with work 

 tables, chemicals, etc., on the left. The building is equipped with 

 electric lights and extension lights for night examination, in addition 

 to gas, and a combined hygrograph and thermograph records the 

 temperature and humidity of the room at all times. For convenience 

 Ave have called this special building a " f onuicarium " — which the 

 office boy invariably confuses with "auditorium" and "natatorium. " 

 Plenty of windows insure full ventilation at all seasons ; and to avoid 

 abnormally high temperatures in summer a second or accessory roof, 

 2 feet above the main roof, breaks the rays of the sun and shades 

 the building proper. The building has also' proven a convenient in- 

 sectary for the breeding of other insects. The Argentine ant pos- 

 sesses a marked proclivity for attacking all insects w^hich one has 

 tinder observation, and all breeding experiments in cages, no matter 

 what the insect, must be protected from the ants. The trays of run- 

 ning water therefore serve to keep the ants away from general cage 

 experiments, as well as to confine the ants to the cages in which they 

 themselves are being studied. 



It may be mentioned that Prof. C. W. Woodworth of California 

 visited this "'formicarium" in the summer of 1908 and so pleased 

 was he with the cages and the plumbing arrangements of the for- 

 micarium that he returned to California and prepared a similar out- 

 fit for the study of the Argentine ant there. 



Establishing Colonies for Study 



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

 is comparatively easy. It is onlj- necessary to secure a fertile queen 

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

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

 have been captured by attracting 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 upon the cage and 

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

 nest proper. At first we experienced some difficulty in preventing 

 them from collecting beneath th^ stand, but it w^as presently found 

 that if a little dirt be removed from another colony and placed in 

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

 adopt it as a suitable home.' After the establishment of such colonies 

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



