BREEDING EXPERIMENTS WITH BREMUS QUEENS. 33! 



queen or workers and then dragged to the. sand pile. Xo other 

 brood being present in the nest, this nucleus was combined with 

 another terricola colony which had been taken on the preceding 

 day.- 



The nesting habits of this species have been dealt with in 

 another paper ('226). 



Borealis GROUP. 



I. Bremns borealis Kirby. 



Four queens of this species, captured in or near the Arnold 

 Arboretum, were experimented with. As no borealis workers 

 could be obtained in the vicinity of Boston, two workers of 

 Bremns fervid us were given to queen No. I (confined May 29), 

 and three workers of Bremus impatiens to queen No. 2 (confined 

 June 6), but neither one of the queens would cooperate with the 

 foreign workers. On June 25, queen No. I was found dead in the 

 nest, whereupon the workers of both queens were liberated, 

 neither queen having started a nest. A somewhat different 

 method was then resorted to. On June 26, about a dozen cocoons 

 of Bremus impatiens from which workers were just beginning to 

 emerge, were given to borealis queen No. 2. . She immediately 

 adopted both, the cocoons and the workers, and on June 28 con- 

 structed an egg-cell and oviposited. Two days later, this mixed 

 colony was permitted to forage out in the open, after a small 

 notch had been made in one of the wings of the queen. When the 

 nest was examined on the following day, the queen was missing 

 and did not return. 



Borealis queen No. 3, captured July 2, was confined with 

 sixteen worker cocoons of Bremus impatiens, which she adopted 

 at once. On the following day, she built an egg-cell and ovi- 

 posited. By July 5, four workers of Bremus impatiens had 

 emerged, and this borealis-impatiens colony was also given com- 

 plete liberty; but eight days later, the queen was found dead 'in 

 a corner of the nest-box, probably as a result of an encounter with 

 the workers. 



Queen No. 4 was confined on July 8 with fourteen worker 

 cocoons of Bremus fervidus, which were adopted immediately. 

 She laid a batch of eggs on the following day, and another on 



