and one of the last four only in 26 cases; while, on the contrary, they selected the plain as one of the first three only in 25 cases, and one of the last four in 75

I may add that I was by no means prepared for this result. Müller, in his remarkable volume on Alpine Flowers, states that bees are much more attracted by yellow than by white. In the same work he gives the following table :

This table does not indeed show any absolute pre

ference for one colour rather than another. In the first place, the number of species compared is very different in the case of the different colours; and in

Alpenblumen, p. 487.

the second place, the results may of course be due to the taste, quantity, or accessibility of the honey (all of which we know exercise a great influence), rather than by the colour of the flower. Still the table rather seemed to indicate that bees preferred red, white, and yellow, to blue.

I may very likely be asked, if blue is the favourite colour of bees, and if bees have had so much to do with the origin of flowers, how is it that there are so few blue ones? I believe the explanation to be that all blue flowers have descended from ancestors in which the flowers were green; or, to speak more precisely, in which the leaves immediately surrounding the stamens and pistil were green; and that they have passed through stages of white or yellow, and generally red, before becoming blue. That all flowers were originally green and inconspicuous, as those of so many plants are still, has, I think, been shown by recent researches, especially those of Darwin, Müller, and Hildebrand.

But what are the considerations which seem to justify us in concluding that blue flowers were formerly yellow or white? Let us consider some of the orders in which blue flowers occur with others of different colours.

For instance, in the Ranunculaceae,' those with simple open flowers, such as the buttercups and Thalic

I take most of the following facts from Müller's admirable work on Alpine Flowers.

trums, are generally yellow or white. The blue delphiniums and aconites are highly specialised, abnormal forms, and doubtless, therefore, of more recent origin. Among the Caryophyllacea the red and purplish species are amongst those with highly specialised flowers, such as Dianthus and Saponaria, while the simple open flowers, which more nearly represent the ancestral type, such as Stellaria, Cerastium, &c., are yellow and white.

Take, again, the Primulacea. The open-flowered, honeyless species, such as Lysimachia and Trientalis, are generally white or yellow; while red, purple, and blue occur principally in the highly specialised species with tubular flowers. The genus Anagallis here, however, certainly forms an exception.

Among the violets we find some yellow, some blue species, and Müller considers that the yellow is the original colour. Viola biflora, a small, comparatively little specialised fly-flower, is yellow; while the large, long-spurred V. calcarata, specially adapted to humblebees, is blue. In V. tricolor, again, the smaller varieties are whitish-yellow; the larger and more highly developed, blue. Myosotis versicolor we know is first yellow and then blue; and, according to Müller, one variety of V. tricolor alpestris is yellow when it first opens, and gradually becomes more and more blue. In this case the individual flower repeats the phases which in past times the ancestors have passed through.

The only other family I will mention is that of the

Gentians. Here, also, while the well-known deep blue species have long tubular flowers, specially adapted to bees and butterflies, the yellow Gentiana lutea has a simple open flower with exposed honey.

Müller and Hildebrand1 have also pointed out that the blue flowers, which, according to this view, are descended from white or yellow ancestors, passing in many cases through a red stage, frequently vary, as if the colours had not had time to fix themselves, and by atavism assume their original colour. Thus Aquilegia vulgaris, Ajuga Genevensis, Polygala vulgaris, P. comosa, Salvia pratensis, Myosotis alpestris, and many other blue flowers, are often reddish or white; Viola calcarata is normally blue, but occasionally yellow. On the other hand, flowers which are normally white or yellow, rarely, I might almost say never, vary to blue. Moreover, though it is true that there are comparatively few blue flowers, still, if we consider only those in which the honey is concealed, and which are, as we know, specially suited to and frequented by bees and butterflies, we find a larger proportion. Thus, of 150 flowers with concealed honey observed by Müller in the Swiss Alps,2 68 were white or yellow, 52 more or less red, and 30 blue or violet.

However this may be, it seems to me that the preceding experiments show conclusively that bees do prefer one colour to another, and that blue is distinctly their favourite.

1 Die Farben der Blüthen, p. 26.

2 Alpenblumen, p. 492.

311

CHAPTER XI.

WASPS.

I HAVE also made a few experiments with wasps.

So far as their behaviour, when they have discovered a store of food, is concerned, what has been said with. reference to bees would apply in the main to wasps also. I will give some of the details in the Appendix, and here only refer very briefly to some of the experiments.

Experiment 1.--Watched a wasp, which I had accustomed to come to my room for honey, from 9.36 A.M. to 6.25 P.M. She made forty-five visits to the honey, but did not bring a single comrade.

Experiment 2.-The following day this wasp began working at least, came to my room for the first time at 6.55 A.M., and went on passing backwards and forwards most industriously till 6.17 P.M. She made thirty-eight journeys, and did not bring a single friend.

Experiment 3.-Another wasp was watched from 6.16 A.M. till 6 P.M. She made fifty-one journeys, and during the day five other wasps came to the honey. I do not think she brought them.

Experiment 4.-Another wasp was watched from 10 A.M. to 5.15 P.M.; she made twenty-eight journeys,