No. 401.] THE FRUITING OF THE BLUE FLAG. 385 
marked unfitness where nature generally shows the finest 
adaptations. ‘Civilization " may well be held responsible for 
this. The larva of the pamphilas feed on grass, and meadows 
and pastures have greatly increased the amount of grass avail- 
able for their food. The butterflies, on the contrary, feed only 
on the nectar of wild flowers; these have correspondingly 
diminished in number; and the supply of nectar available for 
so specialized an insect has become very scant. They visit the 
Iris, because “stern necessity compels.” They are equally 
abundant about the flowers of Geranium maculatum Linn., 
which blooms at the same time, and about every other species 
from which they can get any nectar. Were enough nectar 
available in flowers adapted to them, I think it quite likely that 
they would leave the Iris flowers unmolested. 
I could not satisfy myself as to whether the apparent scar- 
city of the finely adapted bees (the only insects for which the 
nectar of the blue flag is made entirely available) was due to 
the diminishing of the nectar stores by the pamphilas or to 
some more remote cause effecting a decimation in the actual 
number of bees. But they were few about the flowers at the 
most favorable times ; and the foregoing tables zai shown 
the ovules incompletely fertilized. 
I trust I have shown in the foregoing pages that the flower 
should be studied as only one factor in the reproductive 
process, its pollination, one of the links in the chain of cir- 
cumstances, binding together two generations. It should be 
studied (1) in relation to local fauna and flora, (2) in relation 
to latitude, season, and situation, and (3) in relation to chang- 
ing conditions of environment. Past studies of flowers and 
insects, though very numerous, are only complete in having 
completely demonstrated the interdependence of these and in 
having shown the existence of numerous coadaptations between 
them. There are broader ecological adaptations yet to be 
worked out, which may explain the fitting of a species to its 
place in natural society, but which will certainly require the 
coöperation of students, in various places and for a long time, ~ 
content to spend much labor in gathering and correlating 
ecological data. i 
