INTOXICATION OF HUMBLE-BEES ON CERTAIN CAPITULATE FLOWERS. 9 



invariably happened that the insect suddenly turned on its side, 

 and moved the second pair of legs convulsively in the air ; some 

 even turned on their backs, or rolled about on the capitula. After 

 a time a few tried to fly away, but their wings seemed powerless to 

 raise them into the air, so that they fell on the ground instead. Most 

 of them, however, dragged themselves over the florets, greedily 

 searching the same ones over and over again for honey. 



I shut one of the bees thus affected in a tin box, and after about 

 fifteen minutes opened the box. Close by was a large plant of 

 Centaurea Scahiosa, on' which were five helpless bees. The one 

 which had been imprisoned flew away with a loud buzzing noise, 

 described a circle in the air about nine feet above the Centaurea, 

 pounced down upon one of the flower-heads, and in a few seconds 

 was as incapable as ever. On this day the above experiment was 

 many times repeated with similar results. 



On Sept. 8th, about six o'clock in the evening, I was botanizing 

 in a part of South Carnarvonshire where Centaurea Scahiosa does 

 not grow. A Bombus alighted on Scahiosa Succisa, and immediately 

 became helpless. I placed it in my vasculum, putting with it a 

 number of the flower-heads of Scahiosa, and opened the box at 

 intervals of fifteen minutes for two hours. During the whole of 

 that time the bee kept dragging itself from one flower to another, 

 greedily searching the florets for honey, and repeatedly examining 

 the same flowers. It took no notice of any attempts to drive it away 

 further than to raise the second pair of legs, moving them aimlessly 

 in the air. In its inability to fly, and its tendency to fall on one 

 side, it behaved exactly like the bees on the Orme. When, however, 

 the box was opened next morning, the bee had gone as far as it 

 could from the flowers ; when put back upon them, it flew upon 

 the window ; when caught again and prevented from leaving the 

 flowers, it exhibited a most comical appearance of disgust, raising 

 its head and its fore legs as high as it could above the plants, then 

 precipitately hurrying away as soon as released. The greed and 

 avidity shown by the insect the previous evening when persistently 

 keeping its head in the florets, and its helplessness when tumbling 

 about on the flower-heads, were in striking contrast to the dislike 

 and even disgust shown by the same insect the next morning, and 

 its vigorous efforts to fly away from the same flowers. 



On Sept. 13th I was again on the Orme. A Bombus alighted on 

 Centaurea nif/ra, and in two or three seconds showed the usual 

 symptoms of incapacity. Ultimately it fell down to the ground, but 

 in a few minutes it was able to fly again. ' 



The number of humble-bees observed getting intoxicated on 

 C. Scahiosa was so large, and they behaved in a manner so similar 

 to that of those described above, that it would be useless to quote 

 my notes on each individual case observed. In every instance the 

 bees became covered with pollen, and when taken away from the 

 plant they soon recovered so as to be able to fly vigorously, but they 

 alighted again on the first Centaurea available. 



When these observations were first made, the following seemed 

 to be the most striking facts : — 



