April, '09] JOURNAL OF ECOXOMIC ENTOMOLOGY 183 



even when such "off" periods cannot be accounted for by low tem- 

 peratures. 



Fertile queens confined in test tubes without accompanying work- 

 ers will often deposit a few eggs upon the Avails of the tubes, but we 

 have been totally unable to get colonies established by confining 

 queens in artificial formicaries AA-ithout workers accompanying them. 

 This failure has not been due to any need of Avorkers to feed or care 

 for the queen, since she can feed herself from a supply of honey or 

 sugar as readily as can a AA-orker. Ordinarily, she attends to her OAvn 

 toilet and it is doubtful Avhether she is in reality "attended" by the 

 workers in the sense that queen bees are attended. 



Fertile queens do not confine themseh'es to the formicaries, either 

 natural or artificial. Isolated dealated queens are not infrequenth- 

 found wandering about buildings by themselves and, while the queens 

 in artificial formicaries ordinarily stay within the nest proper, they 

 have at times been seen outside of it. The finding of dealated queens 

 wandering about, coupled Avith the fact that Avorkers readily accept 

 a queen from any source, seems to indicate that ncAv colonies may 

 sometimes be established in nature by AA'orkers associating with such 

 Avandering queens. This probable method of colony formation is 

 quite distinct from the pronounced division, or "divisional migra- 

 tion," which is referred to on a subsequent page. 



All immature stages of the queen are as yet unknoAvn. In the tAvo 

 seasons during which colonies have been under almost daily observa- 

 tion, not a single queen has been cleA-eloped in any of the artificial 

 formicaries, though males have been developed in abundance. 



Virgin queens should be easy to discover in areas heavily infested 

 by the species but such is not the case ; nor have Ave been able to de- 

 tect any of the virgin queens AA'hen the males Avere flying in abundance. 

 Only three virgin ciueens haA^e thus far come under our observation. 

 These were found on April 21, 1908, by Messrs. Rosenfeld and Bar- 

 ber, two of my assistants, in the course of examining a very large col- 

 ony which had been driven from a Ioav marshy area by the rising 

 waters of the Mississippi Ri\'er. 



The Worker 



The Avorker measures from 2.25 to 2.75 mm. in length and is well 

 illustrated in figure 4, &. As Avith the queen, the abdomen extends 

 to about the tarsi of the hind legs Avhen the Avorker is active or en- 

 gaged in feeding. The abdomen is capable of considerable disten- 

 sion, and AA-hen the Avorker is fully engorged Avith syrup or other 

 liquid the chitinous plates of the abdomen are forced apart, rendering 



