Pollination of the Primrose. 
103 
getting at it poked its head deep into the mouth of the corolla. 
It naturally stayed longer in the short-styled flowers, hut its 
movements in the long-styled forms were sufficient to pollinate the 
protruding stigma. There would seem to be no doubt that in the 
Church Stretton district these are very active agents of cross¬ 
pollination of the primrose, just as Briggs found them to be at 
Plymouth. They can however only bring about the pollination of 
the long-styled flowers. 
Prom the instances given above, therefore, there is no doubt 
in my mind that primroses are efficiently cross-pollinated in the 
district under observation by Bombylius , Anthophora and Andrena 
with the addition of occasional, though by no means isolated visits 
of Bombas, the same genera indeed to which Briggs attributes the 
pollination of the primrose around Plymouth. The absence of 
these insects during the observations made by Darwin and Burkill 
must I think be due to their observations having been made in 
somewhat exposed situations, at all events this seems very probable 
in the case of Burkill. 
On the days on which I observed insects in the sheltered spots 
which I had selected, I looked in vain for such visitors in large 
primrose covered areas at the foot of Caer Caradoc, which were 
exposed to the west winds which prevailed during my visit. 
In normal Spring weather the slopes sheltered from the east 
wind would probably have yielded positive results, and indeed, on 
one somewhat less windy day several specimens of Bombas were 
noted visiting the primroses here. On that day Apis was also in 
evidence visiting the celandines and wood anemones with which the 
primroses were associated. 
There is no doubt that unfavourable weather is prejudicial to 
the cross pollination in many places owing to the absence of insects 
in those localities. That however, cross-pollination in the district 
under observation must be a pretty general phenomenon is I think 
borne out by the fact that in most of the patches of primroses I 
examined I met with one or more specimens of the so-called oxlip, 
the hybrid between Primula acaulis andP. officinalis. Both parents 
were pretty plentiful in the district and generally specimens of both 
were found near the hybrids. There can, I think, be no doubt 
that these hybrids owe their origin to cross-pollination by insects, 
and as the chances of such hybridisation must be somewhat 
limited in species which differ slightly in their time of flowering, 
the occurrence of a fair number of hybrids argues a considerable 
frequency of insect visitors to both parents. 
