274 SIR JOHN LUBBOCK ON THE 
by the coloured corolla, and surely the simple and sufficient 
reason why it did not light on them was that they contained 
no honey. 
7. 
He treated in a similar way some flowers of an Ipomea purpurea. 
Here, however, I should make the same objection as made to 
Series 4. In this case also he gives no comparison with unmuti- 
lated flowers. 
8. 
I pass over some similar observations on Delphinium Ajacis, 
Centaurea Cyanus, Digitalis purpurea, Antirrhinum | majus, 
Heracleum Fischeri, &c., to which, I submit, the same criticisms 
apply. 
9. 
The next experiment was with the Cornflower (Centaurea 
Cyanus). Bonnier, in his ‘Mémoire sur les Nectaires,’ observes 
that in a field containing white as well as blue Cornflowers 
(Centaurea Cyanus), the Bees seemed (as is indeed probable) to 
visit them both nearly equally. Prof. Plateau says: “ Mes 
observations, tout en confirmant celle de Bonnier, sont plus 
completes.” The Cornflowers observed by Plateau were of four 
colours—blue, purple, rose, and white. He records 16 visits by 
two Hive-bees, and 14 by four Megachiles, and observes that 
" l'indifférence pour la coloration est du reste à peu prés compléte." 
The number of visits seems to me quite insufficient to justify any 
conclusion, but so far as they go they tend to confirm my 
experiments recorded in this Journal, which showed a preference 
for blue, since out of 30 visits recorded by Prof. Plateau, 16 were 
to blue flowers, 6 to purple, 6 to white, and 2 to rose. Prof. 
Plateau adds, however, that “la préférence apparente pour les 
capitules bleus tient à cette particularité, indiquée plus haut, que 
ceux-ci étaient plus nombreux que les autres variétés." He does 
not, however, tell us what the respective numbers of the different 
coloured flowers were, and under ail the cireumstances no con- 
clusion whatever can, I submit, be drawn from tbe observation. 
10. 
He proceeds to dwell on the existence of certain flowers which 
are 1nconspicuous, and yet, in consequence of their strong scent, 
much visited by insects, If anyone denied that scent serves to 
