384 Dr Fulton on the Infiorescence, Floral Structure, and 



any method. On the contrary, altliougli very industrious, 

 they display a total lack of the systematic habits of the bee, 

 and flicker about from one raceme to another in the most 

 arbitrary manner. They visit very few flowers on one 

 inflorescence before passing to another, and then not 

 always to the nearest. Nor do they necessarily visit the 

 female flowers first, but alight indifi'erently on any one, in 

 whatever stage, and at any part of the raceme ; they may 

 pass for a distance up or down, or, what is more common, 

 around the inflorescence, and they frequently return to the 

 same raceme, and even to the same cyme, and after an 

 interval to the same flower. They appear to be entirely 

 guided as to which flowers they should alight on by the 

 presence or absence of nectar, which is visible from the 

 outside. Now it is obvious that this irregular mode of 

 visitation corresponds with the irregular disposition of 

 the flowers in the two sexual stages. It is probable that 

 the interpollination which must frequently occur is ren- 

 dered ineff'ectual by the prepotency of foreign pollen, and 

 since the flowers are most assiduously and repeatedly 

 visited,* cross-fertilisation can scarcely ever fail. The 

 wasp, clinging back-downwards, thrusts in its head above 

 the reproductive organs, which are touched by the under- 

 surface of its head, prothorax, and the basal segments of 

 the anterior legs. 



Bees also occasionally visit the flowers of both species. 

 T have observed four kinds of humble-bees at each, and 

 rarely the hive-bee at S. nodosa. They were all sucking, 

 and the smaller bees scraped pollen on to their under 

 surface. It is interesting to note that while the bees on 

 the whole maintain their ascending h abt, they do not 

 usually systematically visit all the flowers in a raceme 

 before leaving it ; if a flower-bearing cyme of an adjacent 

 raceme is interposed, they generally pass to that. On 

 two occasions I observed a fly eating pollen ; but these 

 flowers are remarkably free from the visits of Diptera, 

 and of the smaller insects which habitually haunt most 

 open flowers. 



* I examined a large number of newly-opened flowers with a lens, and rarely 

 failed to detect abundance of pollen, not only on the stigma but scattered 

 about the lower lip. 



