OO SS ee ee 
ON THE FERTILISATION OF FLOWERS BY 
INSECTS AND ON THE RECIPROCAL 
ADAPTATIONS OF BOTH 
jy Sate the last ten years, since, by his wonderful 
work on Orchids,* Darwin anew turned the at- 
tention of naturalists to the remarkable connection 
Fic. 1.—Head of a humble-bee (Bombus muscorunt L. 9) seen from above, 
with the oral apparatus stretched out to its fullest extent (5; 1). 
between the structure of flowers and the insects visiting 
(4 
Fic. 2.—Sucking apparatus of a honey-bee seen from beneath (rz: 1) 
and fertilising them, many essays on the contrivances of 
* “On the various Contrivances by which British and Foreign Orchids 
ae fertilised by Insects, and on the good Effects of Intercrossing.” London, 
1862. 
187 
flowers as apparently affording facilities for intercrossing 
distinct individuals have been published ; but there is no 
doubt that by far the greatest part of the work on this 
subject is still to be done. The most conspicuous flowers 
attracted, of course, in the first place, the attention of 
inquirers, and much greater pains was taken to show the 
possibility of their cross-fertilisation by insects than to 
observe whether self-fertilisation may possibly take place 
if not visited by insects. Another very obvious deficiency 
of observations indispensable to be made on the subject 
in question resulted,—the fertilisation of flowers by insects 
being studied by botanists but little acquainted with 
insects. From this cause, for the most part, when flowers 
were examined as to their intercrossing by insects, no 
complete observations were made as to the insects them- 
selves which were supposed to visit and fertilise the flowers, 
and in many cases the agency of insects was over-esti- 
mated in consequence of not observing them directly. 
Therefore, being myself acquainted with our flowers as 
well as with a great number of our insects, I thought it 
would be as agreeable as useful if I observed, as far as it 
was possible for me, the insects which really visit and 
fertilise our flowers, their adaptations to gain the honey 
Fic. 3.—Lateral view of the sucking apparatus of a humble-bee (Bombus 
silvarum 1.), representing all the four foldings partly commenced, 
partly imperfectly executed. A piece of the tubular mentum is broken 
away to show the folding of the base of the tongue (7; 1). 
and the pollen, and on the other hand, the adaptations of 
our flowers to the insects that visit them; and having 
during a series of years bestowed all my leisure upon 
observations of this kind, I put them together in a work 
which was published some months ago (“ Die Befruchtung 
der Blumen durch Insecten und die gegenseitigen An- 
passungen beider.” Leipzig, 1873.) Supposing that this 
| book is in the hands of only very few Englishmen, I 
| think it may be of some interest for the readers of NATURE 
if I make them acquainted with the principal new facts 
contained in my work, adding some observations made 
since its publication. 
l.—Jn what manner the hive- and humble-bees obtain 
the honey of the flowers 
The first accurate description and drawing of the parts 
_ of the mouth of the hive-bee were given by Swammerdamm 
| about two centuries ago, but he did not succeed in finding 
out the true function of the tongue ; he described and drew 
it as perforated at the end,* and believed that it was a 
simple suckin pipe. His successors saw that the tongue 
* “Joh, Swammerdamm, Bibel der Natur, Aus dem Hollandischen 
iibersetzt.” Leipzig, 1752. Taf. xvii. 
