DIAGNOSING BEE DISEASES IN THE APIARY 33 



mens of the sick bees are usually of normal size but often appear 

 swollen or, less frequently, shrunken. Some of the sick bees retain 

 their hairs until they die, whereas others become partially or entirely 

 hairless, probably because their hairs are pulled out by healthy bees. 

 Loss of hairs is accompanied by a darkening of the abdomen and 

 thorax and a shiny or greasy appearance. 



The most characteristic symptom of paralysis is weakness and a 

 trembling or shaking movement of the body and wings, frequently 

 accompanied by hairlessness and sprawled legs and wings. Sick 

 bees that are motionless will sometimes show the trembling move- 

 ments when disturbed. Some of the symptoms given here for paral- 

 ysis are also present in other disorders of adult bees and cannot be 

 depended upon alone for diagnosis. Trembling, weakness, and hair- 

 lessness, particularly when accompanied by dark, shining abdomens 

 and sprawled legs and wings, seem to be the most dependable symp- 

 toms of paralysis. Bees in this condition tend to collect on top of 

 the frames. A diagnosis can sometimes be made by carefully open- 

 ing the hive, disturbing the colony as little as possible, and examin- 

 ing the bees on the top bars of the brood nest. 



TRANSMISSION 



It has been found by beekeepers that combs of brood from colonies 

 with paralysis can be given to healthy colonies without spreading 

 the disturbance and that the bees emerging from these combs remain 

 healthy. In experiments at the Bee Culture Laboratory, combs of 

 honey and pollen from affected colonies were placed in a healthy 

 colony without paralysis being transmitted. When all the combs 

 of an affected Italian colony were replaced with combs of brood 

 from a healthy Caucasian colony, paralysis appeared among the 

 young Caucasian bees within 2 weeks after the first of them emerged. 

 Paralysis appeared to be transmitted when sick bees and young 

 healthy ones were confined in the same cage. When young healthy 

 bees were wet with water containing the macerated remains of 

 affected bees, paralysis also appeared to be transmitted. The results 

 of these experiments seem to indicate that paralysis is slightly infec- 

 tious and spreads directly from sick or dead bees to healthy ones. 



SENDING SAMPLES FOR LABORATORY EXAMINATION 



If only a small amount of brood or a few bees are affected, or the 

 symptoms are unusual, it is sometimes difficult to make a definite 

 diagnosis in the apiary. Examination by laboratory methods is 

 then necessary. It is also desirable at times to have diagnoses made 

 in the apiary verified in the laboratory. 



HOW TO PREPARE SAMPLES OF BROOD 



In sending samples for laboratory examination, the following in- 

 structions should be followed: (1) Cut a sample of comb at least 

 4 by 5 inches in size. (2) Be sure that the sample contains as much 

 of the dead or discolored brood as possible. (3) No honey should 

 be present, and the comb should not be crushed. (4) Mail the 



