320 



figures aud supj)osiiig that they can keep up for twenty minutes, no 

 matter how heavily hiden ou the return trip, the rate of speed on the 

 outgoing would take them 10 or 12 miles from the home line." 



It is quite difficult to determine the rate of speed attained in flight 

 by bees. Therefore any computation of the distance they go after 

 honey which is based upon their supposed speed is liable to great error. 

 The number of wing-strokes per second, 190, as recorded above, was 

 obtained by Prof. Marey* by what is known as the " graphic method." 

 A bee was held so that when its wings were in motion one of them 

 would strike very lightly the surface of a revolving cylinder covered 

 with smooth paj^er slightly smoked, and at the same time a style fixed 

 in the end of a tuning-fork was arranged to record on the paper the 

 vibrations of the fork. The tone of the latter being known, and hence 

 also the number of vibrations it makes per second, it was easy to com- 

 pare the number of these actually recorded with the record of the 

 bee's wing for the same time, and thus arrive at the number of strokes 

 the bee makes in a second. It is evident, however, that the friction of 

 the bee's wings against the i)aper must lessen somewhat the number 

 of strokes, and indeed Prof. Marey observed that as he lessened this 

 friction the velocity increased considerably. If the note made by the 

 bee's wings when she is in vigorous flight could be accurately deter- 

 mined, the corresponding number of vibrations required per second to 

 produce that pitch would represent the wing-strokes made by the bee 

 causing the sound. Dr. H. Landoist thinks the note of a bee in full 

 flight ranges from A to C of the first and second, leger of the treble clef. 

 This gives over 400 vibrations per second. If, then, " 190 strokes per 

 second would propel the bee forward at the vate of a mile x^er minute " 

 (a claim by no means to be accepted as proven), and if Landois has 

 determined the note correctly, over 2 miles per minute would be the 

 speed attained. 



Conservative authorities are disposed to place the rate of speed at- 

 tained by bees much below 30 miles per hour, even no more than 18 to 

 20 miles, and nothing is better recognized than that bees when fatigued, 

 when flying from flower to flower, or when returning heavily laden to 

 their hives, proceed far more slowly than when outward bound. Thus 

 the calculation that they go 10 or 12 miles from home is plainly erroneous. 



However difficult it is to determine their rate of speed, and hence 

 however erroneous any calculations based ui)on such determinations 

 may be, it is not at all difficult to tell practically how far bees actually 

 do go after honey. Apis melUfica has been introduced into regions 

 where the species did not exist before, and careful observations have 

 been made regarding the range of its flight, and also the yellow varie- 

 ties have been taken to countries or localities where only brown or 



* Animal Mechanism: A Treatise on Terrestrial and Aerial Locomotion. By E. J. 

 Marey. (International Science Sei'ies), 1883. 



t Die Ton-nnd Stimmaparate der Insekten. Von Dr. H. Landois. Zeitschrift fur 

 wissenschaftliche Zoologie, 1867, p. 105. 



