242 



disease, and regarding it in the same light as a bacterial 

 infection, seeks the cause amongst the experiences of 

 the stock during the previous week or two. We now 

 know that in the majority of cases he must go back a 

 much longer period of time for the origin of the disease. 

 In the case of sudden and extensive mass crawling 

 the period is probably shorter than otherwise if we are 

 correct in regarding this crawling as the first, resulting 

 from the orignal infection from the outside. It may 

 not, however, be so. In other cases where this symptom 

 commences in limited numbers and increases gradually, 

 it would appear reasonable to assume that the initial 

 infestation has been slight and that the later increase in 

 the numbers of infested bees is the result of the spread 

 of the parasite within the four walls of the hive — all 

 the offspring of the original intruders. The progress of 

 the disease in this instance is therefore more gradual, 

 and acute or sudden collapse of the stock is not an 

 accompaniment. 



Crawling in Assodatioti with Swaitning. 



A particular case of " mass crawling " and one of 

 the commonest experiences of summer in relation to 

 this disease is the appearance of sudden and extensive 

 crawling in a swarm, whilst no such symptom has been 

 recognised in the parent stock. In the course of ex- 

 aminations of affected bees of such swarms my ex- 

 perience has been to find that the degree of infestation 

 in the majority of the crawling bees is an advanced one. 

 Also not infrequently the proportion of crawling bees 

 to the whole swarm is high. 



If the stock yielding such a swarm be examined it 

 will be found that it also has a proportion of infested 

 bees although as yet mass crawling may be absent, and 

 possibly even the solitary or stray crawler also. 



Hitherto, under such circumstances, it has been 

 usual for the beekeeper to speak of the swarm as con- 

 tracting the disease before the stock of its origin, and 

 it has sometimes been suggested to me that the source 

 of infestation was under the circumstances almost 

 certainly to be found in the hive in which the swarm had 

 been placed, or on the old combs within it. 



