20 MISCELLANEOUS PAPERS ON APICULTURE. 



As long as the colony is strong the wax moths can do no damage, 

 but as the bees decrease in number the combs offer a foothold to one or 

 other of the moths and within a very short time the whole hive is one 

 mass of wax moth tunnels, larval excreta, and cocoons. The combs 

 are completely destroyed and nothing remains but the web and a mass 

 of debris on the hive bottoms. If the moth larvae actually ate the 

 infected material, they would serve to remove the infection where the 

 bee keeper is too careless to do so — as is too frequently the case. 



The two wax moths differ greatly in their habits in some respects, 

 but it is not the purpose of this paper to discuss these points. The 

 large wax moth {Galleria mellonella L.) is the most widely dis- 

 tributed and is found in practically every part of the United States, 

 and probably wherever the honey bee is now kept. The lesser wax 

 moth (Aohroia grisella Fab.), on the other hand, is not so widely dis- 

 tributed, but it is known to exist in various localities in this country. 



WOBK OF THE LARGE WAX MOTH. 



(Galleria mellonella L.) 



Plate I is from a photograph of a comb, infected with American foul 

 brood, on which larvae of the large wax moth were placed. The comb 

 was placed in a box to exclude light and was laid flat on a piece of 

 paper. The larvae at first worked on the under side of the comb, but 

 gradually they got to the upper surface. It will be noticed that in 

 one part of the comb the lower side walls of the cells remain intact ; 

 here the dried-down scales of American foul brood were thickest, and 

 evidently this was the center of the brood during the time of infection. 

 The remainder of the area formerly occupied by comb is nothing 

 but debris, with a few scales scattered here and there. Evidently 

 only where scales are thick do they hold together enough to stand 

 upright. To show how the scales stand up, the web was removed 

 from the surface. The background of the photograph is merely a 

 piece of paper. 



Plate II is a photograph of a rough box used for a hive during 

 some experiments in producing American foul brood by the feeding 

 of pure cultures of Bacillus larow. a The five frames of this small 

 hive contained thousands of the dried-down scales so characteristic 

 of this disease. The box was put away in a closet and the large wax 

 moth got into it, with the result that all the combs were completely 

 destroyed. The webs and empty frames were removed for this photo- 

 graph. The black mass in the bottom of the box is composed of 



o Circular No. 94, Bureau of Entomology, entitled, " The Cause of American 

 Foul Brood," by Dr. G. F. White. Issued July 29, 1907. 



