148 Mr Burkill, On the Fertilisation of some [Feb. 12, 



lisation is any criterion, it is nearer to M. saliva ; for it never 

 enters the 'very-explosive state' of M. falcata. The Hive-bee 

 was an extremely abundant visitor, almost enjoying a monopoly. 

 The flowers are scented and nearly the whole of an inflorescence is 

 in blossom at the same time. But, in spite of the abundant 

 visitors, OO^/o of the flowers, after remaining open for 8 or 9 days, 

 withered unfertilized. The bees sucked the flowers from one side 

 as in M. saliva. Anxious to make out what particular attraction 

 this plant offered to the bees (these being ten times as abundant 

 on it as on a similar neighbouring plant of M. saliva), I visited the 

 Botanic Gardens on several occasions at 6 a.m. and observed the 

 first bees return to work after the night. Many plants compete 

 for the bees' attention on the ' Leguminosae ' bed, but, except on a 

 single occasion when one bee repeatedly tried to force open some 

 closed Melilotus flowers, M. silvestris not only received the first, 

 but also the greatest number of visits. Experiments were then 

 made to see if the buzzing of one bee will attract others to the 

 plant on which it is buzzing. Bees were imprisoned in flowerless 

 plants in the neighbourhood of the patch of M. silvestris, where 

 they were allowed to buzz freely. The results were partly aflirma- 

 tive. Evidently the bees had learnt by experience that this 

 medick offers abundant honey. 



The list of insect visitors bears out the fact that it is the 

 flowers which the inconstant butterflies fertilise, that need the 

 brilliant colours : M. silvestris certainly was not freely visited by 

 Lepidoptera. 



Insect-visitors in the Cambridge Botanic Gardens, none of 

 which were seen exploding the flower. 



Hymenoptera aculeata: — 1. Apis mellifica L $ very 

 abundant ; 2. Borahus hortorum L. 3. B. lucorum L. 



4. Odynerus parietum L % . 



Lepidoptera : — Rhopalocera : — .5. Pieris brassicae L. 



Diptera: — Syrphidae : — 6. Platychirus manicatus Mg. 

 7. Syrphus halleatus Deg. 8. 8. luniger Mg. 9. S. coroUae F. 

 10. 8. ribesii L. 11. Sphaerophorea scripta L. 12. Erystalis 

 pertinax Scop. 13. Syritta pipiens L. Sarcophagidae : — 



14. Sarcophaga carnaria L. Muscinae : — 15. Lucelia sericata Mg. 

 Anthomyidae : — 16. Garicea tigrina F. 



M. lupulina L. 



Mechanism. The explosive arrangements in this little flower 

 are just as in M. saliva, but the tension is much less, the stigma 

 being only just brought up to the vexillum in explosion. The 

 flowers are small and massed together. The rough areas on the 

 petals are similar in position and shape to those on M. saliva. 

 As a rule the flower closes about 5 p.m. ; but, while investigating 



