REARING BUMBLEBEES IX ARTIFICIAL NESTS. 53 



CONSTRUCTION OF ARTIFICIAL NESTS AND TECHNIQUE. 



My first serious experiments in confining the queens began in 

 the spring of 1915 and were continued each spring of 1916, 1917, 

 1919, and 1920. As early as 1910 I tried to get queens to start 

 nests in confinement, but the methods then employed were so 

 poor that I will not review these futile attempts. It was not 

 until 1917 that I succeeded in getting colonies by this method 

 (1917). For confining the queens I used, in 1917, a small 

 wooden box 5 inches by 7 inches by 2 inches. At one end of 

 this box was a round opening which could be closed by the 

 insertion of a cork. For the top I used small ruby or amber 

 colored glass sections. During the intervals between exami- 

 nations a dark cloth was wrapped about the box to exclude the 

 light. In one corner of the box remote from the grass nest was 

 placed a small tin, in which liquid food was supplied to the queen. 

 In 1919 and 1920, I used boxes for confining the queens similar 

 to those used in 1917. 



Within these boxes I used various materials for making the 

 conditions such that a queen would be induced to start a colony. 

 Naturally, because the queens of bumblebees select the nests of 

 field mice the first material used was the soft, day grass from such 

 nests. Field mice always select a fine quality of grass for their 

 nests and hence grass from such a source needs no further sorting 

 or treatment. The nests, however, are not always easy to find 

 and oftentimes I was hard pressed to get enough of the grass 

 from this source for my experiments. Sladen experienced the 

 same difficulty in getting suitable grass to use in domiciles for 

 attracting bumblebee queens. I found that the best time and 

 place to look for nests of this type was in early spring along a 

 railroad right of way, after the ground had been burned over to 

 destroy the coarser vegetation. The nests so located usually 

 escaped destruction by the fire and were then easily perceived. 

 The difficulty experienced at times in getting enough of these 

 nests, led me to try to find a substitute for the finely sorted grass 

 they contained. Cotton did not have enough "body" and the 

 small cotton fibers became enmeshed continually with the pollen 

 supplied the queen. The silk from milkweed pods likewise 

 proved to be too light and fluffy, as was the case also with raw 



