1 6 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
large, and even in the generally bad apple years, 1918 and 1920, almost 
every variety in the large collection at the Garden has borne a heavy 
crop, so much so that each year prophets have been numerous who 
have said that they could not possibly bear many in the next year. 
Now no amount of care and attention to cultural details can 
induce fruitfulness in a large orchard unless pollen-carrying agents 
are present in sufficient force to ensure adequate cross-pollination of 
the blossoms. Few bees are kept in the neighbourhood of the orchard, 
and during the last few years even that small number has been greatly 
reduced by disease. 
Careful observations have been made by various members of the 
staff, and especially by one of us, on the insects visiting apples, and 
we find that while hive bees are generally present in the warmer parts 
of bright fine days, in dull and stormy weather they are not to be seen. 
On the contrary, whether the weather be fine or dull, other insects 
are present and at work, and, unless the weather be so severe or so 
extremely stormy as actually to kill the stigmas or the ovary of the 
flower, pollination is going on by their aid. In 1920 on no occasion 
did we find a single hive bee at work on the apple flowers, yet in 1920 
the crop of apples was as good as one could wish for. 
Among the insects visiting the apple flowers in addition to hive 
bees, humble bees take a foremost place. They work at least as hard, 
and they work earlier and later than the hive bees, in good weather 
and in bad — in fact we have a note of one or two being at work in the 
flowers during a snow shower ! Our notes show that on every day 
but two in 1920 and two in 1921, when the apples were examined 
during the blossom-time, humble bees were at work, while frequently 
even in 1921 hive bees were not seen on the trees. Several species 
were often found, especially Bombus lapidarius, B. terreslris and B. 
lucorum. On some occasions the " carder " bee, B. muscorum, was 
present, and more rarely B. heifer anus. Pollen clings easily to the 
hairy bodies of these bees, and, while they carry much away, they are 
apt to leave some on the stigmas of the flowers they visit. 
Other hairy wild bees belonging to the genus Andrena, and to 
allied genera, are also numerous, and active. 
Next to these the most numerous visitors are hover flies : two- 
winged flies so named from their habit of hovering in the air and 
suddenly darting off a yard or so. Species of the genus Eristalis 
are sometimes very abundant, and so also are species of Syrphus and 
allied genera both large and small. They are pollen feeders, and 
probably keep less consistently to one tree than do hive and humble 
bees. 
Midges and small two-winged flies are also numerous on most 
occasions, and though their visits to flowers appear less purposeful, 
in the aggregate the amount of pollen distributed by them must be 
considerable. 
All these insects may be regarded as the normal visitors of apple 
flowers. In addition, there is a very long list of other insects taken at 
