io4 F- F. IVeiss on the Pollination of the Primrose . 
I did not come across any of the beetles Meligethes pieipes , 
(Sturm) which Christy found so frequently on the primroses in Essex; 
nor was I able to observe any butterflies alighting on primroses, 
but that may have been due to the scarcity of Lepidoptera owing 
to the cold weather. No observations were made at night as the 
severe night frosts seemed to preclude the possibility of nocturnal 
visitors to the flowers. 
Self Pollination. 
That self-pollination may occur fairly often in the primrose 
cannot be denied, and indeed, Darwin observed the frequent 
presence in both the cowslip and the primrose of Thrips which he 
considered aided the self fertilization of both forms. 1 In many 
primroses which I examined numbers of Thrips were present and 
in these flowers it was very common to find pollen grains scattered 
throughout the tube of the corolla and it seemed likely that it had 
been carried about there by these small insects. 
Another agency for self-pollination is no doubt the wind taken 
in conjunction with alterations in the position of the flower. I 
agree with “ Field Naturalist” in thinking that too little importance 
was attached by Darwin to the effect of the wind. At all events in 
the absence of cross-pollination which must frequently happen in 
flowering plants, in early spring the strong winds of that season 
are probably of considerable use. Watching the primroses on the 
hill-side, much exposed to the wind and in which the absence of 
insects as stated above was very marked, the violent shaking of 
the flowers was a noticeable feature. 
This must however be considered in conjunction with the 
singular adaptation for self pollination which I think is shown in 
both the primrose and the cowslip, in the changes in position of 
the flower. In the primrose the flowers open at first in a vertical 
position and if the flower is short-styled the pollen from the opening 
anthers can readily be shaken by the wind on to the lower standing 
stigma. But towards the end of the flowering the flower stalk has 
grown considerably in length and the flower passes into a horizon¬ 
tal and often a pendant position so that the long-styled forms have 
a chance of self pollination too, when the flowers are agitated by 
the wind. It may be thought that this movement is mainly for 
the concealment of the fruits which in the primrose are ripened 
beneath the foliage, but though this may be to a certain extent the 
case, I cannot but believe that the self-pollination is also a 
1 Darwin., l.c., p. 37. 
