v 
68 T/ie /risk Naturalist, April, 
one at least — possibly both — of the pollen masses or 
pollinia, adhering to its proboscis or to its face. I went 
to a small bog where Orchis maculata was growing in 
very great abundance — so abundantly that it would cer- 
tainly have taken an enormous multitude of insect visitors 
to fertilise all the flowers. I gathered here one spike, and 
examined all its open flowers — nineteen in number. In 
only one of the nineteen flowers — the uppermost and 
therefore the most recently opened — I found both the polhnia 
still present. In three others one pollinium was left 
while one had been removed. In all the remaining fifteen 
both pollinia had been carried away. I then went to a field 
that was not so well adapted for bog-loving plants, where 
a single spike of Orchis maculata was growing by itself. 
I opened its flowers, beginning with the lowest and there- 
fore longest expanded, and I found in every flower both 
polhnia still in their places. No bee or other useful insect 
had been to that Orchis, though hundreds and hundreds of 
such insects must have been at work at flowers of its kind 
in a bog not half a mile away. That was isolation on a very 
small scale. What would be its chance of fertilisation if that 
plant of Orchis maculata had been growing on an island 
separated by miles of sea from the nearest ground where 
another plant of its kind occurred ? 
But I now come to a strange case of an apparent de- 
parture from rule, which has been a subject of special 
interest to me for the past eighteen years. On June 3rd, 
1895, walking through a wood in County Wexford, I 
noticed a specimen of the Common Carder Bee (Bombus 
muscorum, as we used to call it, though I am told I must 
now, to my great regret, call it Bombus agrorum) gathering 
honey from a flower of that pretty Vetchhng, Lathyrus 
macrorrhizus, or the Heath Pea. I watched it, and found 
that after imbibing nectar from two or three plants of 
Vetchling it suddenly descended on a flower spike of the 
blue Bugle (Ajuga reptans), but after gathering from that 
it went again to Lathyrus. So long as I watched that bee 
it moved about dividing its attention between those two 
plants, but touching no others. About half an hour after- 
