4 INTRODUCTION 
of certain insects, one must at the same time find it not improbable that there 
should be some provision for preventing this nectar from being spoiled by rain, 
and that these hairs may have been placed here for the attainment of this purpose. 
. In the following summer I investigated’ the forget-me-not (Myosotts palustris). 
I found not only that this flower has nectar, but also that the nectar is completely 
protected against rain. At the same time, however, I was struck by the yellow ring, 
which surrounds the opening of the corolla tube, and which is so beautifully conspicuous 
omues sa Oa ltiifertyfeln. Mg 
ERAS) 
bei aT iss dem zitern. 
ih w ith ae 
[So 
aM 
Fig. 1. Reduced title-page of Sprengel’s book, taken from the edition edited by Knuth (in ‘ Klassiker 
der exakten Naturwissenschaften,’ vols. xlviii-li). 
against the sky-blue colour of the limb. Might not, I thought, this circumstance 
also have some reference to insects? Might not Nature have specially coloured 
this ring, to the end that it might show insects the way to the nectar reservoir? 
With this hypothesis in view, I examined other flowers, and found that most of 
them confirmed it. For I saw that flowers, in which part of the corolla is 
differently coloured from the rest, always have spots, figures, lines, or dots of 
peculiar hue just where the entrance to the nectar reservoir is situated. I now 
