HYMENOPTERID FLOWERS 



ri7 



through the holes bitten by this humble-bee. In the Alps, Bombus mastru- 

 catus Gersl. 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 Miiller ('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 Ike same time and place, are as a 

 rule 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 



Fig. 27. Mu7nhle-bc£ Flowers- (i) SaK'ia pratensis Z.., a Humble-bee Flower witli levci" mcclianisra. 

 (2) Medicago satlva A., a Hamble.bcc 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 

 MuUer 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. 



' Frank ('Untersuchongen ijber die Farben der Bluten,' p. 30. Tubingen, 1S25) long ago called 

 attention to such contrasts in colour between related species : these two contr.-isted colours, i. e. 

 blue and yellow, he says, frequently appear in different speciei of the same genus, e. g. the genera 

 Linum, Scabiosa, Aconitum, Lupinus, Iris, .ind others, include species with pure blue and pure 

 yellow dowers. 



