LEPIDOPTERID FLOWERS 125 



Many Butterfly Flowers are distinguished by an agreeable and often very 

 powerful odour, that not infrequently resembles vanilla, and this strongly attracts 

 the special visitors. 



Molh Floivers, as Sprengel long ago stated ('Entd. Geh.,' p. 16), are white 

 and devoid of nectar-guides (cf. p. 6). They possess, however, an odour that is 

 frequently very powerful, and which is perceived from a great distance by the moths 

 which visit and pollinate them. Kerner (' Nat. Hist. PI.,' Eng. Ed. i, pp. 208, 209), 

 for example, narrates that during the daytime he marked a Convolvulus Hawk-moth 

 (Sphinx convolvuli) with vermilion, and set it down at a distance of 100 metres 

 from a honeysuckle plant (Lonicera Caprifolium). ' When twilight fell the hawk- 

 moth began to wave the feelers which serve it as olfactory organs hither and thither 

 a few times, then stretched its wings and flew like an arrow through the garden towards 

 the honeysuckle,' When Kerner got there, he found the moth sprinkled with ver- 

 milion fluttering in front of the honeysuckle flowers and sucking nectar. It must 

 therefore have perceived the odour of the blossoms from a distance of 100 metres. 



The strong aromatic odour of the flowers belonging to this group becomes 

 especially noticeable towards evening, while by day it may entirely or almost entirely 

 disappear. Moth Flowers open exclusively or chiefly at dusk. The most highly 

 specialized flowers of this group are those in which the nectar is hidden so deeply 





Fig. 37. Hawk-moth Flowers, (i) Lilium Martagon Z. (2) Lonicera Periclymenum Z.. 



that it can only be rifled by Hawk-moths (Sphingidae), in which the proboscis is 

 extremely long. As these Lepidoptera have the habit of sucking nectar as they 

 hover before the flower, many Hawk-moth Flowers (e. g. Lonicera Caprifolium and 

 Periclymenum, Lilium Martagon) are characterized by anthers which are but loosely 

 attached to one point of the filament, so that they readily touch the body of the moth 

 as it hovers in front of them (see Fig. 37). 



The stamens of other species of this group of flowers do not exhibit the pecu- 

 liarity just described at all, or only to a slight extent, e.g. Platanthera bifolia, Silene 

 nutans and inflata, and Convolvulus sepium. 



Although the last-named species is visited during the day by insects, especially 



by bees, its chief poUinators are moths, of which the most important is Sphinx 



i-"onvolvuli. According to F. Buchanan White (J. Bot., ii, 1873), Convolvulus 



Njpium seldom fruits in England, where the Convolvulus Hawk-moth is uncommon, 



^and in Scotland, where this insect does not appear to occur, the plant is very rare. 



