HYMENOPTERID FLOWERS 117 
through the holes bitten by this humble-bee. In the Alps, Bombus mastru- 
catus Gers/. is distinguished above all other humble-bees ‘by its constant habit— 
destructive to the flowers—of getting nectar by forcing an entrance to deep and not 
easily accessible nectaries.’ 
Lepidoptera here again behave as in Bee Flowers proper. Other visitors are 
almost without exception pollen-thieves (Knuth, ‘ Bliitenbesucher,’ II, pp. 6 and 7). 
Hermann Miller (‘Alpenblumen,’ pp. 499 et seq.) has dealt very thoroughly with 
the colours of Bee Flowers and Humble-bee Flowers. He calls attention to the 
fact that flowers of this class which are in bloom at the same time and place, are as a 
tule of diverse colours. Miiller recalls the circumstance that several species of the same 
genus, with exposed or only partially concealed nectar, are often in flower beside one 
Fic. 27. Humble-bee Flowers. () Salvia pratensis Z., a Humble-bee Flower with lever mechanism. 
(2) Medicago sativa Z., a Humble-bee Flower with spring mechanism. 
another at the same time, and possess the same hue, e.g. Ranunculus acris, bulbosus, 
and repens. Even, however, in the case of flowers with completely concealed nectar, 
accessible to short-tongued insects, similarly coloured species are in flower together, 
e.g. Sempervivum, Mentha, and numerous Compositae (especially Cichoraceae). 
The colour relations between closely allied Bee Flowers blooming simultaneously 
in the same district are, on the other hand, of quite a different nature. Hermann 
Miiller contrasts the following species with one another’ :— 
Aconitum Lycoctonum—yellow ; A. Napellus—blue ; 
Lamium album—white; L. maculatum—red; Galeobdolon luteum—yellow. 
Salvia glutinosa—yellow ; S. pratensis—blue. 
Teucrium montanum—white ; T. Chamaedrys—purple. 
Pedicularis tuberosa—whitish-yellow ; P. verticillata—purple. 
Trifolium badium—yellow to brown; T. montanum—small white capitula, 
standing high; T. repens—larger white capitula, standing low; T. pratense var. 
nivale—still larger, dirty white capitula ; T. alpinum—purple. 
1 Frank (‘Untersuchungen iiber die Farben der Bliiten,’ p. 30, Tiibingen, 1825) long ago called 
attention to such contrasts in colour between related species: these two contrasted colours, i.e. 
blue and yellow, he says, frequently appear in different species of the same genus, e.g. the genera 
Linum, Scabiosa, Aconitum, Lupinus, Iris, and others, include species with pure blue and pure 
yellow flowers. ’ 
