ENTOMOLOGY. 769 



ually neglected, in which honey has been placed. They cease their 

 visits when the neetiferons portions of flowers are removed and begin 

 them again when honey is placed in flowers so treated. The experi- 

 ments were performed by counting the number of visits per hour to 

 certain tlowers. For example, 4 individuals of Megachile ericetorum 

 showed no preference for the various colors of Centaurea cyanus; the 

 first went from white to bine, from that to purple, and thence to white 

 tlowers. The second from white to bine, thence to blue. The third 

 from rose to purple and thence to white. The fourth from blue to rose, 

 to blue, and thence to blue. Similar observations were made in con- 

 nection with rose, scarlet, yellow, orange, and white varieties of Dahlia 

 variabilis ; likewise in connection with Scabiosn atropurpurea, Linum 

 grandiflorum, and L. usitatissimum, and the results compared with 

 those obtained by Darwin with Dietamnus fraxinella, Delphinium con- 

 solida, Primula veris, and by Bonnier with Centaurea cyanus, Althea 

 rosed, Digitalis purpurea, K p Hob 4 ion spicatum, and Brassica oleracea. 

 In regard to color Plateau's results are entirely confirmatory of those 

 obtained by these authors. 



The activity of worker bees in the collection of honey, L. 

 Defour (ISApiculteur, 40(189? ), No. 12, pp. 300-312, figs. 6).— The daily 

 and hourly variations in weight of a hive of bees were studied during 

 the season of 1896 with a view to obtaining light on the relations 

 between the going aud coming of the workers, the number of bees, the 

 honey collected, etc. The first weight taken in the morning was chosen 

 as the zero point from which to measure the variations. The hourly 

 weights were used in platting curves. As a result of the weighing, it 

 was found that at Fontainebleau there are li periods of good honey 

 flow and 2 of bad. The first of the latter begins the season and is 

 followed by the first of the former extending from the latter part of May 

 into June and July. Most of the summer is occupied by the second of 

 the poor periods of honey flow and is followed by the second period of 

 good honey flow, beginning in August and extending into September. 

 The first of the 1* periods of good honey flow is due mostly to aeacia 

 and the second to heather bloom. It was also found that during periods 

 of comparatively poor honey flow the daily curve obtained shows pecu- 

 liar and characteristic features. The bees during the first hour or hour 

 and a half in the morning leave the hive in small numbers and then at 

 the end of this time begin to depart in very large numbers, so that the 

 hive sinks rapidly in weight. Finally a point of minimum weight is 

 reached, after which the weight of the hive begins to increase, slowly 

 at first and then more rapidly. It then begins to decrease again until 

 it reaches in the afternoon a second minimum weight, after which it 

 progressively increases in weight until the evening. By comparison 

 with the experiments by Bonnier on the flow of nectar, Defour comes 

 to the conclusion that this rise in the weight of the hive during the 

 middle of the day corresponds to the period of small How of nectar, 

 which occurs during the hottest part of the day. 



