THE FLIGHT ACTIVITIES OF THE HONEYBEE 3 



right angles to one of the springs, so that as the bee passed between 

 the springs this wire was pushed into a small cup of mercury, thus 

 closing the electric circuit. It is a simple enough matter to get a 

 bee to form such a contact, but to get each contact to represent the 

 passage of but one bee proved to be exceedingly difficult and is per- 

 haps impossible. Seven different devices of this sort were con- 

 structed and tested, each intended to overcome some defect inherent 

 in those preceding. Regarding these devices, it suffices to say that 

 none of them proved practical. One of the chief difficulties was 

 the fact that the springs may be so delicately adjusted that on the 

 passage of a bee a contact may be formed by the head and thorax 

 and then another contact formed by the abdomen. Yet another bee 

 passing these same springs in a slightly different manner may get 

 through without forming any electrical contact whatever. An at- 

 tempt was made to overcome this difficulty by taking advantage of 

 the smaller constriction which exists between the dorsal surface of 

 the propodeum and the abdomen ; that is to say, the bee was forced 

 to walk in an upright posture, through a tube of special cross sec- 

 tion, so that the spring passed over this dorsal region. The bees, 

 however, showed great reluctance to go through such a tube. 



George S. Demuth and N. E. Mclndoo, both formerly con- 

 nected with the Bee Culture Laboratory, have informed the writer 

 that they, too, have given some thought to this problem. Mr. 

 Demuth attempted to get the bees to push against prongs placed 

 equidistant around a revolving wheel, much on the principle of the 

 undershot water wheel. Doctor Mclndoo tried to get the bees to 

 push against small hinged gates. Neither attempt was carried to 

 completion. 



Owing to the fact that the stimulations of bees to flight, such as 

 light intensity, nectar flows, and other environmental factors, vary 

 greatly in degree, and also that individual bees apparently differ 

 somewhat in their reactions to even slight obstacles placed in their 

 way, it is questionable whether any apparatus working on the prin- 

 ciple of having the bees push against a mechanism will ever be found 

 practical. 



Attention was then turned to the possibility of utilizing the weight 

 of the bee to form an electrical contact. Three models were con- 

 structed on this plan, each proving to be a step in advance. The 

 third model, after several long tests, appeared to be the instrument 

 required. After a few minor improvements in the design, 30 such 

 instruments were built, 15 to accommodate outgoing bees and 15 for 

 incoming. These instruments are referred to in this paper as 

 " gates." 



This device (fig. 1) may be described as a miniature balance on 

 jeweled pivots. As the bee enters the tunnel fixed to one end of the 

 lever, its weight, having a greater moment than the counterbalance, 

 causes the tunnel to drop and this movement produces three con- 

 secutive results: (1) It closes the door to prevent a second bee from 

 gaining entrance to the case while the tunnel is on its downward 

 stroke; (2) it establishes an electric contact by thrusting two plati- 

 num prongs attached to but insulated from the lever, into two 

 mercury cups; and (3) it opens a. second door on a lower level, per- 

 mitting the bee to fly to the field or to enter the hive, as the case may 



