nonchalant manner. Even when a dried and neglected
mnseum-specimen, mites have avoided this butterfly,
while they have destroyed other insects in the same
box or cabinet-drawer. Its caterpillar feeds on a genus
of Asclepiadacese (Gomphocarpns) which is everywhere
abundant and also possesses distasteful qualities, so
that its whole existence seems to be environed by
natural chevaux de frise. How is it, then, that this
insect does not positively swarm 1 is the question I
frequently asked myself when watching the numbers
which everywhere pursued this highly protected life.
There must evidently be some great check at work,
or the propagation of the species must result in prodigious
flights, which would surpass anything to be
seen in the whole Ehopalocerous order. I am inclined
to think that these highly protected butterflies, which
experience an immunity from attack on account of
distasteful qualities or resemblance to some inanimate
object or other protected insect, may have some inherent
weakness or danger which produces great mortality in
their early stages and that the wonderful protections we
observe thus only enable them to escape extinction.
This view would help to explain how .it is that the extraordinary
guises by which natural selection has enabled so
many insects to escape the attacks of their enemies have
not led to an enormous increase in their numbers. It is
the weak that require protection, and like consumptive
patients who live by escaping the rigors of a northern
winter by visiting a warmer clime, but still possess the
inherent weakness of their system, so nature grants
these insects immunity from one danger, which allows
them a possibility of surviving another. We know by
the great gaps between the continuity of some species
in the same genus how many must have reached
oblivion in the struggle for existence, and I look on
these “ protected” insects as surviving by such means
some incipient mortality of which we are at present
ignorant,, or their numbers must indefinitely increase.
I carefully watched the Danais in the endeavour to find
some danger to its life and the means by which its
Hemisaga prtsdatoria, n. sp.