OLFACTORY SENSE OF THE HONEY BEE 269 



of the celloidin surrounding each piece was allowed to remain in 

 the open air until the celloidin became firm. The pieces of mate- 

 rial embedded in celloidin were then placed in a second vial con- 

 taining a solution of three parts of chloroform and one part of 

 55° M. P. paraffin. It was again boiled for 10 minutes in the 

 same manner as described above. It was then removed from this 

 solution and infiltrated for 10 minutes in 55° M. P. paraffin inside 

 the paraffin bath and finally was embedded in the same paraffin. 



Serial sections were cut 6 and 10 microns thick and were mount- 

 ed on slides in the usual way. These sections were stained on 

 the slides with iron hematoxylin and eosin and also with safranin 

 and gentian violet. The former double stain is the better for 

 sense cell differentiation, but had it not been for the use of the 

 latter double stain, the manner in which the sense fibers termi- 

 nate would not have been clear. 



When all the foregoing steps were carefully followed, good serial 

 sections were had in abundance, but none were perfect, owing 

 to the hard chitin. In fact these were only celloidin sections em- 

 bedded in paraffin, although other celloidin sections, 35 microns 

 thick, of entire adult workers were made by following the usual 

 celloidin method. These were stained with Ehrlich's hematoxylin. 



The drawings were made at the base of the microscope with 

 the aid of a camera lucida, and all are original except figure 24, 

 which was copied from Schenk ('03) to illustrate the anatomy of 

 the antennal organs. 



EXPERIMENTS ON BEES IN AN OBSERVATION HIVE 



In order to ascertain the sensitiveness of workers to various 

 kinds of odors in their natural environments, for comparison 

 with the results in observation cases, an observation hive was 

 constructed from a 10-frame Langstroth hive. The ends and 

 sides were replaced by glass except a mere framework, the two 

 end glasses being fastened permanently, while on each side were 

 two pieces of glass so arranged as to slide. Thus an opening of 

 any size could be made on the sides so as to expose the bees on 

 the combs. The ends and sides had wooden shutters which fitted 

 snugly against the glass, making the interior of the hive dark, 



