POLLINATION OF THE BRITISH PRIMULAS. 105 
The Pollination of the British Primulas. 
By Muer Curisty, F.L.S. 
[Read 1st December, 1921*,] 
SYNOPSIS. PAGE 
I.—Introductory Remarks .,,.....,..,..............,....... 105 
IT.— Observations on Insect Visitors ,.,,..,........,,,.,...,,..., 108 
IIL—The Depths of the Corolla-tubes of the Flowers............ 123 
IV.—The Tongue-lengths of the Insects known to visit the Flowers, 125 
V.—Summary of Observations on Insect Visitors ...........,., 126 
VI.—Critical Remarks on the Observations ..,.........,...,... 129 
VII.—Conclusion.....,...,........ poses rss ere users 134 
I.—Introductory Remarks. 
Forty years or so ago, one often heard or read papers dealing with some 
special point in connection with the pollination (then called “ fertilization”) 
of flowers by insects. At that time, the whole subject was practically new, 
having recently been brought to the front as a result of the superb experi- 
mental and observational work of Darwin. Since then, the chief problems 
involved have been solved, largely through the labours of our past-President, 
Sir John Lubbock (afterwards Lord Avebury), Alfred W. Bennett, John 
Scott, the Rev. George Henslow, I. H. Burkill, and others in this country, 
but mainly through the work of German observers, two of whom have 
published almost-encyclopædic works on the subject. Yet there is still 
much to be learned in detail as to the means by which the flowers of certain 
plants secure pollination, 
Of few plants, if of any, is this more true than it is of the British members 
of the genus Primula. Indeed, the precise means by which the flowers of 
these plants (especially the Primrose) secure adequate pollination has long 
been, and still remains, a complete mystery, though there has been much 
discussion, and close attention has been given to it by many observers, 
including Darwin t, T. R. Archer Briggs f, Hermann Müller $, myself ||, 
* Revised slightly May 1922. 
t Journ. Linn. Soc., Bot. x. (1869), pp. 437-454, and ‘Different Forms of Flowers on 
Plants of the same Species,’ pp. 22, 36, &e. (1877). 
+ Journ. of Bot. (Seemann's), viii. (1870), pp. 190-191; Trans. Plymouth Instit. iv. (1872), 
pp. 180-190; and * Flora of Plymouth,’ p. 279 (1880). 
$ ‘Die Befruchtung der Blumen durch Insekten,’ pp. 346-347 (Leipzig, 1873), and ‘The 
Fertilization of Flowers,’ transl. and ed. by Prof. D'Arcy W. Thompson, pp. 383-386 (Lond., 
1883). 
|| See post., p. 107 n. 
