Samman and Gatenby — Acarine or Isle of Wiyht Bee, Disease. 361 



a White's queen cage, and the wooden top rephiced by a piece of excluder 

 zinc allowing free access for diseased bees, but preventing the drones getting 

 out. It was examined on the 8th day, so that drones were seven or less days 

 old. The drones were infected. Each time the drones were removed and the 

 frame was returned to the White's cage. The experiment was repeated on 

 sLx occasions, i.e. on the 7th, 6th, 5th, 4th, 3rd, and 2nd days, and diseased 

 drones were found. In the tracheae of a drone two days old or less, one mite 

 and two eggs were seen (PI. XVIII, fig. 3). In the trachea of a drone less 

 than twenty-four hours, one mite alone was seen. This seems to prove that 

 the gravid female gains access to the trachea very early and rapidly commences 

 to lay eggs. 



Experiment to show that the hrood is free from infection. 



The Aberdeen workers concluded that the brood is not diseased before 

 emergence. Miss Harvey carried out a number of experiments, and our results 

 confirm her findings. The following is taken from our notes on one of our 

 experiments in this department. 



(August 8th.) A frame of brood from a native stock infected with Acarapis 

 was put into a "White's" queen cage, and a fertile Italian queen placed on the 

 comb; tliis frame was then put in the hive from which the brood was taken, 

 but no bees were able to get access to the comlj. (14th.) Removed the cage. 

 Some young bees had emerged from the cells and the queen had commenced 

 laying. Two more frames of brood now added — one from the same stock, 

 the other from a stock of Acarapis infected bees, to which a Camiolan queen 

 had been introduced on July 3rd. The young bees from this queen had 

 been examined on August lOtli and found infested with Acarapis. (19th.) These 

 three frames were now placed in an upper brood chamber above a strong colony 

 (diseased) with a screen of wire gauze between the chambers. (20th.) Added 

 three more combs of capped brood from diseased colony. (25th.) Put the six 

 frames of brood into a nucleus hive, and transferred them to a fresh locality 

 and allowed young bees to have their first flight. (September 7th.) Transferred 

 frames to a permanent hive. Queen laying well ; brood in all stag'es. (Novem- 

 ber 22ud.) Examined bees, no trace of Acarapis : shut up for winter. 



1923. (February 27th.) Examined bees, no trace of Acarapis. (March 28tli.) 

 Examined bees, no trace of Acarapis. (April 11th.) Spring cleaned hive; bees 

 doing well; brood in all stages; plenty of stores. (July 7th.) Stock swarmed 

 (a very large swarm). Eemoved surplus honey (about 100 lb.) ; this in a poor 

 honey season. At the present d&te (April, 1924) this stock is still doing well. 



Experiments on Diseased Stocks. 



Four stocks were treated with drugs in food during the winter months of 

 1923-1924. As is well known, during the colder period of the year the stoclvs 

 are usually fed on some type of commercial candy. The drugs used by us were 

 mixed with the latter, and by this means the bees were treated in four different 

 ways. 1. Succus Allii of about 15 per cent., in water, sugar added as necessary, 

 according to thickness of food desired. 2. Yadil candy of 2^- per cent. 

 3. Succus Allii of 15 per cent., followed by a treatment of Stockholm tar in 

 candy of 5 per cent. 4. Yadil, as above, followed by Stockliolm tar as above. 

 We found that the bees would take candy syrup containing as much as 30 per 

 cent, of Succus Allii, but not so freely as when the strength of the latter was 

 reduced to 15 per cent. Consequently we worked with 15 per cent, strength. 



Of the four hives the three treated as in paragraphs 2, 3, and 4, all died 



