DETERMINATION OP AGE IN HONEY-BEES. 203 



appearances at the various ages promise to give most inter- 

 esting results as to the cause and effects of disease, as well as 

 the elucidation of many points in the life-history of bees^ feuch 

 as the process of elaboration of the varying bee foods — 

 royal jelly, etc., — and the ages at which these activities are 

 carried on. 



It is a pleasure here to express thanks to Prof. G. C. 

 Bourne, in whose department this work is being carried on, 

 and to my husband, Mr. B. S. Goodrich, for their interest and 

 valuable advice during the progress of the work. Mr. J. B. 

 Gatenby has also made many helpful suggestions in connec- 

 tion with the treatment of insects for cytological examination, 

 r also wish to record that this work on bees is being carried 

 on by means of a grant from the Development Commissioners 

 of the Board of Agriculture. Much assistance in obtaining 

 bees suspected of disease has been given by Mr. A. G. L. 

 Rogers, and more recently by Dr. Keeble and his assis- 

 tants in the Horticultural Section of the Food Production 

 Department. 



StJMMAEY. 



For the study of those bee diseases with which no specific 

 organisms have so far been identified, it is important to- be 

 able to eliminate bees dying of old age, and this cannot be 

 done with certainty by observing outward symptoms. How- 

 ever, the age of bees, which normally work almost incessantly 

 for about six weeks and then die, may be determined with 

 some accuracy from a study of the brain-cells. With advanc- 

 ing age the cytoplasm of these cells undergoes gradual 

 reduction peripherally, until in senescence only a vestige is 

 left surrounding the, nucleus. 



The condition of the head-glands, including a pair of oeso- 

 phageal glands which do not appear to have been previously 

 recorded, gives some indication of age in normal healthy 

 bees. 

 Univeesitt Mitsbum, 

 Oxford ; 

 September, 1919. 



