21 



not cjaimed by Cheshtre, and the belief is not grounded on bacte- 

 riological findings. »White himself did not succeed in finding any 

 bacteria in bees died from paralysis that produced the disease. 

 Suspicions that moulds may be the canse of the tronble have, how- 

 ever, been expressed in that country as seen from a communica- 

 tion in Gleanings of Bee Culture (Barstow 4). The interesting 

 but rather vague ideas of the Irouble are stated in the following 

 way: »When plenty of honey is coming in, the bees show no sign 

 of sickness, but låter in the summer or fall the bees may get some 

 honey containing pollen that might be poisonous, or that has sour- 

 ed, or grown moiild}^ to a certain extent; so that when they feed 

 on it, it is in the right condition to cause what might be called 

 constipation.» 



2. The toxicity of moulds to the honey bee. 



The bees used in the following feeding experiments were Ualians 

 and ordinary black ones. They were kept in spacious boxes co- 

 vered with glass and w r ire gauze. The cages were placed in a 

 warm room (25° C — 28° C) and darkened with paper. The fungous 

 material was mixed with honey, somewhat diluted with sterilized 

 water, and given the bees in sterilized food cups covered with 

 gauze to prevent the insects from getting drowned. The boxes, 

 when used several times in dilYerent series, were repeatedly clean- 

 sed and flushed with boiling water. Two of the moulds used in 

 the experiments, Penicillium sp. 1 and Penicillium stolonifenim Thom 

 were isolated from the intestines of dead bees, kindly supplied from 

 the Entomology Department, Experimentalfältet. The others were 

 isolated from honey-combs. They were grown in slanted 150x30 

 mm. agar-agar tubes, the medium used being of the same composi- 

 tion as the one described in Turesson 24. 



Penicillium sp. 



Series I. 



June 27. 16 bees were used. 0.5 grams of spores and mycelium 

 were mixed in 10 cubic centimetres of honey. The bees showed 

 sign of uneasiness already the same day, and frequently cleaned 



1 This species is probably new, and will be described in detail at anöther occa 

 sion. 



