268 The Fertilization of Salvia splendens by Birds.  { April, 
1: The narrow and elongated tubular form of the corolla quite 
effectually excludes those which are large enough to set the lever 
in motion; 2. If such an insect, for instance a hive bee or small 
humble bee, should force its way into the tube, by the time its 
~ head had reached and elevated the sterile end of the lever, the 
tip of its abdomen would have passed the lowering polliniferous 
end, so that no pollen would reach the insect, and the object of 
the motion would be defeated. Bees might, to be sure, visit the 
flowers solely for their pollen, and I have no doubt that they 
occasionally, do so, in which case they,must often render some 
service in their fertilization, as is the case in so many flowers 
visited for pollen alone. Bees being excluded for the reasons 
above given, we turn to Lepidoptera, which sometimes visit 
the flowers, their long and slender proboscides enabling them to 
reach the nectar with little exertion; but it remains to be shown 
that these organs are sufficiently large or rigid to set the stamens 
in motion. Even if it should be shown that the large nocturnal 
moths do move the levers, which I am far from believing to be 
the case, the brilliant scarlet color is one ill adapted to render- 
ing the flowers conspicuous in the twilight or night, and, so far 
as I know, one which is never possessed by flowers especially de- 
pendent upon these insects for their fertilization; beside which, we 
do not find that close constriction of the mouth or anterior part 
of the corolla bespeaking adaptation to the Lepidoptera. It ap- 
pears, then, that when these insects visit the flowers of our sage, 
they may be of some use in transferring pollen, since their heads 
may encounter stigma and anthers, but they do this without ren- 
dering the motility of the latter of any value. 
The only alternative, then, is birds, which, to be of the highest 
use in this connection, must be found in the native habitat of the 
plant, must visit flowers frequently for nectar, small insects at- 
tracted by the latter, or for both, and finally, must have slender 
and elongated beaks capable of insertion into the tubular flowers. 
All of these conditions are fulfilled by many of the humming 
birds, which reach their greatest number in both species and in- 
dividuals in Equatorial America. The color ef this Salvia is one 
of the most attractive to humming birds, and a glance at Figure 4 
will show that one of those with an elongated beak cannot fail to 
operate the lever in the most perfect manner; its extensible 
tongue, however, rendering it by no means necessary for its beak 
to equal the corolla in length. 
