MAIN RESEARCHES OF PLATEAU. 149 



bees, butterflies, and syrphids showed not the least choice, though no 

 figures were given. During one period of observation pollinators went more 

 frequently to purple heads of Scabiosa purpurea and during another to the 

 rose ones, the explanation being that this was due to the greater number 

 of heads in each case. Observations by Darwin, Bonnier, and Errera and 

 Gevaert were also cited in confirmation of these results, and the conclusion 

 was reached that, contrary to the general view, insects exhibit the utmost 

 indifference to the diverse colors to be found in the same species or the same 

 genus. 



Addition of honey to vivid nectarless flowers. — In the same paper were 

 reported the results of experiments made upon showy flowers with little 

 or no nectar, in confirmation of the views of Darwin, Bonnier, and Pe'rez, 

 who had found that nectar brought visitors in abundance. The flowers of a 

 border of Pelargonium zonale were observed to be completely disdained by 

 Apis and Bombus. A drop of honey direct from the hive was placed in each 

 flower of 17 umbels on plants arranged in a continuous series and marked to 

 prevent confusion with normal ones. Bombus terrestris made 8 visits in an 

 hour to the honeyed flowers, entirely neglecting the neighboring nasturtiums. 

 After sipping at several, he would fly toward the normal flowers, but only 

 to inspect them without alighting. The next day honey was taken from 

 these flowers by 3 A pis, 5 Bombus, and 3 Vespa, as well as several Diptera, 

 and a little later by 18, 5, and 5 individuals respectively of the same genera, 

 but no further visits were seen for the normal flowers. Flowers of Phlox 

 paniculata, which were but little visited by diurnal insects, were provided 

 with honey, a drop being placed in 20 flowers of the violet and white varie- 

 ties. The latter, being in the shade at the time, received no visits, while 

 6 were made to the former by A pis, Pieris, and Vespa, the two bees also 

 making 9 visits during the next period to both colors. Honey was placed 

 on 6 out of 29 white flowers of Anemone japonica, which were ordinarily 

 little visited except by Diptera. During the hour 100 visits were made to 

 intact flowers and 94 to those with honey, making an average of 4.5 for each 

 of the former and 15.6 for the latter. A single flower of Convolvulus sepium, 

 which had been completely neglected, received 29 visits after being supplied 

 with honey, though few of these were made by bees. 



The effect of removing the supply of nectar was determined in Dahlia by 

 excising the disk-flowers of 8 heads and replacing them by a small disk cut 

 from a yellowed leaf of cherry. No insect alighted on the mutilated heads, 

 though Bombus and Megachile inspected them frequently. This behavior 

 determined, the disks were coated with honey and the visitors immediately 

 returned, Bombus making 26 visits, Vespa 12, and Megachile 2 during a 

 half-hour. Two days later the artificial disks were dry and the mutilated 

 heads were again entirely neglected. The disks were removed and a little 

 honey placed in the greenish cup of the receptacle, when visitors came in 

 abundance. The summary stated that insects go without hesitation to 

 flowers habitually neglected by reason of the absence or paucity of nectar, 

 when they are supplied with artificial nectar in the form of honey. They 

 cease their visits, even in the presence of the showy ray-flowers, when the 

 nectariferous part is removed, and begin them again when honey is added. 



