On the Species of the Genus Primula in Essex. 195
Darwin shows ('Forms of Flowers,' p. 36) that Primroses
are fairly fertile when protected from insects [? large insects],
but that the long-styled flowers are, under these circum-
stances, by far the most productive. He also says (Ibid.,
p. 36):—"It is surprising how rarely insects can be seen
during the day visiting the flowers, but I have occasionally
observed small kinds of bees at work ; I suppose, therefore,
that they are commonly fertilized by nocturnal Lepidoptera";
and after saying that bees commonly visit the Cowslip, he
adds (p. 56):—"The Primrose is never visited (and I speak
after many years' observation) by the larger humble bees, and
only rarely by the smaller kinds ; hence its fertilization must
depend almost exclusively on moths. There is nothing in the
structure of the flowers of the two plants which can determine
the visits of such widely different insects. But they emit a
different odour, and perhaps their nectar may have a different
taste." Now on this point I must again differ somewhat from
Mr. Darwin, as I have not unfrequently seen humble-bees
visiting Primroses. A specimen of Anthrophora acervorum in
the middle of March last visited five flowers growing near
together in Westley Wood, Saffron Walden ; and my friend
Mr. H. Richardson, of Newcastle, observed a common large
banded humble-bee visit four flowers on three different plants
near together in the beginning of May, 1881; he has also
seen a bee visit the Hybrid Oxlip. On one occasion, in the
beginning of March, 1882, I saw a honey-bee pay fourteen
visits to flowers on four plants growing near one another in
our garden ; but the insect seemed to have a difficulty in
reaching the nectar, and rejected many flowers altogether.
In the first week of April, 1883, I observed three medium-
sized humble-bees (Bombus sp.) visiting freely quite a number
of Primrose-flowers in Westley Wood; and on May 1st, in
Hyde Wood, Little Yeldham, the day being very warm, I
noticed a number of individuals of Anthophora acervorum at
many flowers. One of these visited the P. elatiori-vuligaris
many times ; another, very unmethodically, visited Primrose
sixteen times, Violet five, Primrose one, Violet four, Primrose
nine, and Violet once, after which I lost sight of it. I also