64 
NATURE NOTES 
mentioned here. One is that “ every known heterostyled plant 
depends on insects for fertilisation and not on the wind ” ; the 
other, that “ heterostyled flowers stand in the reciprocal relation 
of different sexes to each other.” 
Dr. Weiss’ observations were made during eight days in the 
middle of April (1903), near Church Stretton in Shropshire. His 
conclusions were drawn from the examination “ oi two large 
patches of primroses ” adjoining each other, and “ of large 
primrose-covered areas at the foot of Caer Caradoc.” The 
former adjoining situations were “sheltered”; “the large prim- 
rose-covered areas were exposed to the cold west winds of the 
season.” The results which Dr. Weiss arrived at from these 
eight days’ observations are told us in the final paragraph of 
the pamphlet. “ From the observations I have made on the 
primrose, I feel convinced that it is both regularly visited and cross- 
pollinated by insects under favourable climatic conditions, but that 
like most flowers adapted to the visits of insects, it is provided 
with efficient means of self-pollination ” (italics ours). 
In this result it is evident that Dr. Weiss’ observations and 
conclusions do not furnish any support to Darwin’s theory as to 
“ heterostylism.” It was our special purpose in that portion of 
the “ Primrose and Darwinism ” which relates to the primrose 
to controvert by actual evidence these theories of Darwin. Dr. 
Weiss merely maintains that in positions “ where favourable 
climatic conditions” existed the primrose “is regularly visited 
and cross-pollinated by insects ” ; but in the “ large primrose- 
covered areas” he owns, as we shall see below, that “insects 
were markedly absent.” Our remarks here will consequently 
solely refer to an examination, whether the insects he enumerates 
as seen by him visiting the primrose under favourable climatic 
conditions could be, even under such conditions, sufficiently 
efficient agents for the cross-pollination “ of two large patches 
of primroses.” 
Before, however, the matter of the regularity of insect visits 
to the primrose is discussed, we must primarily state that we 
cannot agree with Dr. Weiss’ statement that the primrose “ is 
like most flowers adapted to the visits of insects.” 
The tube of the corolla of the primrose averages 12 to 14 
mm. in length (25 mm. being the equivalent of an inch), and in 
favourable situations it is very frequently 16 mm. long. This 
length excludes the vast majority of insects, and even the 
majority of what are called the “ long-tongued insects, as the 
humble-bees, from reaching the nectar. The humble-bees con- 
sequently are not accustomed to visit it. Only one humble-bee, 
Bonibus liortorum, could reach the nectar with any facility. Its 
proboscis averages from 12 to 17 mm. The proboscis of the 
remaining humble-bees rarely exceeds ii mm., their average 
length being 7 to 9 mm. (Muller). The hive bee could not reach 
its nectar, as its tongue is only 6^ mm. Only two other genera 
of insects, Anthophora and Bombylius (a Diptera), have a proboscis 
