POLLINATION OF THE BRITISH PRIMULAS. 121 
examine flowers of either the Primrose or the Oxlip (but especially the 
former), provided the weather has been warm and sunny, and the state of 
development of the flowers such that the anthers of many plants were 
dehiscing actively. On such occasions, one can count (in the case of the 
Primrose, at any rate) on finding at least one beetle in nearly every tube, 
several in many tubes, and six or seven in some; while, on one occasion, 
I saw at least ten in a single tube*. Yet on cold wet days, or very early or 
very late in the flowering-season, before the anthers have begun to dehisce or 
after they have finished, one sees very few of these beetles f. In the flowers 
of the Cowslip (which, unlike the two other species, grows largely in the 
open), the beetle is met with much less commonly—perhaps because, at the 
time the Cowslip flowers, there are also in flower many other species of 
plant on whose pollen and nectar the beetle may feed. 
How regular and widespread is this beetle’s habit of frequenting the 
flowers of Primula may be gathered from the fact that, apart from my own 
observations on it in Essex, the Rev. M. C. H. Bird and the Rev. E. T. 
Daubeny $ have both found it abundantly in Primroses in Norfolk | and 
Burkill in Yorkshire f ; whilst Mr. Dallman has found it and other members 
of the genus in Primroses in North Wales **, On the Continent, I have 
seen it (or some very similar species) in Oxlips in Belgium ; Müller has seen 
it (or some other member of the genus) in Cowslips in Thuringia ff ; Knuth 
mentions it as occurring in the Primrose in Schleswig-Holstein ff ; and 
Cobelli has recorded the occurrence of two other members of the genus 
(M. umbrosus and M. erythropus) in Primroses in Italy $$. 
Yet some observers have failed to detect the presence of this beetle in the 
flowers—possibly because either it does not occur in their districts or the 
weather was unfavourable at the time of their observations. Thus, Darwin 
does not mention having seen it, though he mentions having seen Thrips, 
which are much smaller creatures. The Rev. E. Bell also failed to observe 
* [n a wood near Saffron Walden, on 5 April, 1883. 
T For instance, on 15 April, 1905, the Rev. E. T. Daubeny found them in 40 per cent. 
of a number of Primrose flowers he examined ; but, on 8 May following, in the same flowers, 
he could find none (see Nature Notes, xvi. p. 116). 
t Nature Notes, xv. (1904), p. 96. 
$ Op. cit., xvi. (1905), p. 116. 
|| Both record the species as Eusphalerum primule, an identification which is probably 
erroneous, though this species does frequent Primroses and other flowers in spring and early 
summer. It is a small, rather elongated, black and brown beetle, 2-3 mm. long, and it 
is common locally, but 1 am not familiar with it as a frequenter of Primroses in Essex, though 
Burkill noted it in Yorkshire. l 
q Journ. of Botany, xxxv. p. 179. 
** Journ. of Botany, lix. (1921), p. 320 et seg. 
tt Nature, 10 Dec., 1875, p. 111 n. 
tt ‘Flower Pollination,’ iii. p. 549. 
§§ Verhandl. zool.-bot. Gesellsch. Wien, xlii. (1893), p. 78. 
