198 On the Species of the Genus Primula in Essex. 
on hot days a dozen or more beetles, belonging to this species 
or a very closely allied one, may generally be found in the 
flowers of the Dandelion or Charlock, which, if taken and 
shaken into one’s hand, readily take wing and fly away. In 
going down the tube of both forms of flower they have a 
struggle to pass the anthers and the stigma ; and I have seen 
both 1. and s. flowers containing beetles in which the sides of 
the stigma were well covered with pollen, as if the insects 
brushed against them. If it should be proved that the beetles 
are the fertilizers of Primroses, Darwin’s explanation will 
merely have to be modified a little. The reciprocal cross¬ 
fertilization of the flowers would be as easily accomplished in 
this way as in any other, for the beetles in passing up and down 
to the nectary would have precisely the same effect as a bee’s 
proboscis in conveying the pollen. 46 The case stands as 
follows:—There are three species of Primula closely allied, 
and very similar in the structure of their flowers. We know 
that two of them (Cowslips and Oxlips) are regularly fertilized 
by bees, but the little beetles just mentioned so seldom 
frequent these that after an examination of many thousands 
of flowers I have come to the conclusion that the beetles 
enter them rather by accident than by design; and, as it is 
not known what insects fertilize Primroses, it seems at least 
possible that these small beetles may be the active agents. 
Although Mr. Darwin protected his Primroses from the 
larger insects, these small beetles may have got unobserved 
through his nets and effected their fertilization, thus 
accounting for the vastly greater degree of fertility possessed 
by Primroses over Cowslips under the same conditions. 46 
45 My cousin, Mr. B. W. Christy, who has observed the number of 
beetles frequenting the flowers, suggested to me that Darwin’s belief in 
the Primrose being fertilized by nocturnal Lepidoptera is untenable, as 
there are very few such insects abroad in the early spring when Primroses 
habitually blossom. 
46 This seems the more probable, as I suppose that in heterostyled 
plants (especially the long-styled forms) fertilization is impossible, except 
through the agency of insects. 
[Darwin observed that when both were protected by a covering of gauze 
the long-styled Primrose-plants produced more seed than the s,; and it 
