THE POLLINA TION OF THE PRIMROSE 67 
rose, seems to have had almost an exactly similar experience to 
my own. He met with an Anthophora, a Bumbyliits, a Brimstone 
butterfly and Andrana Gwymina {Jour, of Boi., vol. iii., 190, 
“ Devon and Corn. Nat. Hist. Soc.” vol. iv.). 
Mr. J. H. Burkill says, “ The fertilisation of the primrose is 
still unexplained ” — if cross-fertilisation alone can explain it, it is, 
and will remain, unexplained ! — “ None of the insects .seen on it 
through many hours of watching are sufficient for its fertilisa- 
tion.” He continues “ The doubt does not end with our own 
shores. Knuth at Kiel has failed to observe insect-visitors, and 
Cobelli in the Tyrol can, besides four beetles and Thrips, only 
name one butterfly {Gonepteryx rhamni) as a visitor capable of 
cross-fertilising the plant. He especially notes the fact that 
bees avoid it. My night observations have been few and not 
conducted with best conditions and without results.” * 
Hermann Miiller omits all mention of it in his book — “ The 
Fertilisation of Flowers.” This is the more noticeable as the 
book was written in the special advocacy of the cross-fertilisation 
of flowers. Darwin also says “ the primrose is never visited — 
and I speak after many years of observation — by the larger 
humble bees, and only rarely by the smaller ones.’’’ The smaller 
humble bees have with one exception [B. hortorum) only an 
average length of proboscis of 7-9 mm. ; nor do any of these 
smaller bees, e.g,, the “ worker ” or “ neuter ” bees, come 
out hatched from the nest till May at the earliest, when the 
primrose season is almost past. Darwin was consequently 
driven under his theory about “ heterostylism ” to suppose that 
the primrose was fertilised by night-flying Lepidoptera. In 
support of this opinion Darwin had not, and there is not, a 
shred of evidence. 
Mr. Scott Elliott, in the “ Flora of Dumfriesshire,” says, 
“ Bomhus hortorum, regular and sufficient.” What evidence he 
had to substantiate such an absolute dictum we are not informed. 
The above sentence is all that he says in his book about it. We 
confess grave doubts as to the value of such a brief and summary 
testimony, as it stands in direct contradiction to Darwin’s, 
Burkill’s, Knuth’s, Corbelli’s and Muller’s negative evidence. 
It is a far too common practice for mere casual observers when 
they see an insect on a flower to assume positively that such a 
flower is generally cross-fertilised by such insect ; they come to 
this conclusion at once without any special or extended observa- 
tion. They are too apt to forget the adage — which applies 
particularly to this relation between flowers and insects — “ One 
swallow does not make a summer.” 
Evidently the testimony of the different observers mentioned 
above affords no evidence, but the contrary, in support of Dar- 
win’s theories about “ heterostylism,” viz., that “ one form of 
Primula must unite with the other form in order to produce full 
fournal of Botany, May, 1897. 
