The meadow lark on the fence post behind my house is unusually voluble
this uncertain morning; maybe he is getting his day's singing off
before the sun shall hide, discomfited, behind the unrolling cloud
furls. A solemn grackle, with yellow eyes and bronzed neck, stalks
with cocking head in the wet green of the well-groomed front lawn; a
whisking bevy of goldfinches, which chat to each other in high-pitched
hurried phrases, disposes itself with much concern in the bare tree
across the road, and swinging along overhead, a woodpecker cries its
harsh greetings. But the life here on the street is tame and usual
compared to that busy living and to those eventful happenings taking
place in a remoter corner of the garden. There where the warm dust is
figured with the dainty tracks of the quail hosts and the flower-flies
hum their contentedest note; there in that half-artificial, half-wild
covert of odorous vegetation, a life in miniature, with the excitement
and stresses, the failures and successes and the inevitable comedies
and tragedies of any world of life is going on, with the history of it
all unrecorded.
Mary has just come to call on me, bringing an unkempt bouquet of
Scotch broom from the garden. On these branches of broom are many
conspicuous white spots. They are not flowers, for it is not broom
flower time, and the flowers are yellow when their time does come. But
these white spots, soft little cottony masses, like little pillows or
cushions, and with regular tiny flutings along the top, have puzzled
Mary, and she has come to ask me about them, for I am supposed to know
all things. Well, luckily, I do happen to know about these, but I
suggest that we go into the garden together and see if we can find
out. The truth is, I am glad of an excuse to get away from this
tiresome German book about _Entwicklungslehre_. And then, too, I want
to look at things and talk with Mary.
Mary has such a fascinatingly serious way of doing things that aren't
serious at all. She has got the curious notion lately that many little
people live among the grasses, the grass people she calls them, and
that that is the reason there are so many very little white flowers
coming up in my lawn. My own notion had been that some rascally
seedsman had sold me unclean grass seed, but Mary's notion that the
grass people are planting and raising these little flowers for their
own special delectation is, of course, a much wiser one. So when we
walk on the lawn, we go very slowly, and I have to poke constantly
among the grasses with my stick as we move along so that the little
people may know we are coming and have time to scurry away from under
our great boots.
When we got out to the row of brooms, we found many of the soft white
cushions on all the bushes. But some of them were torn and
dishevelled. And in these torn masses many tiny round particles could
be seen. These little black specks are simply eggs, insect eggs, as I
told Mary, and soon she had discovered among them some slightly larger
but still very small red spots which were waving tiny black feet and
feelers about. They were of course the baby insects just hatching from
the eggs.
"Does the mother lay the eggs in these little white cushions and then
go away and leave them?" asks Mary.
"No, she stays right by them," I answer.
"But where is she then? I can't--Yes I can too," cries Mary in great
triumph. "Here she is at one end of the egg cushion. She is a part of
it."
"Well, no, not exactly," I have to say. "It is part of _her_, or
rather she spins the cushion, which is really a sac or soft box of
white wax, in which to lay her eggs. Something the way the spiders do,
you know. Only their egg box is made of silk and usually fastened to a
fence rail or on the bark of a tree and left there. But some of the
spiders, the large, swiftly running, black kinds that live under
stones, carry the silken ball with the eggs inside about with them,
fastened to the end of the body. Well, this cottony cushion scale
insect--that's its right name--keeps its waxen sac of eggs fastened to
it, but as the egg sac is much larger than the insect itself, it can't
run about any more, but has to stay for all the rest of the time until
it dies in the spot where it makes the sac. However, as it gets all
the food it wants by sticking its slender little beak into the broom
or other plant it is on and sucking up the fresh sap, it gets on very
well."
"But what makes some of the egg cushions--how pretty they are,
too!--so torn and pulled open," asks Mary, who has listened to my long
speech very nicely. She often gets impatient when I lecture for too
many minutes together.
"That is for you to find out," I say. "There is a dreadful thing going
on here if you can only see it. But a rather good thing too. Good for
the broom bushes anyway, and as they are _my_ broom bushes and I like
their flowers, good for me."
Just then a very stubby, round-backed, quick little red beetle with
black spots walked off a broom stem on to Mary's hand. She didn't
scream, of course, nor even jerk her hand away. She may learn when she
is older to be frightened when pretty, harmless, little lady-bird
beetles walk on her. But now she likes all sorts of small animals, and
is not afraid at all.
Mary is not at all slow to understand things, and when this
hard-bodied little beetle, with a body like half a red-and-black
pill, walked off the broom on to her hand, she guessed that he might
have something to do with the torn-up egg cushions. So it didn't take
her long to find another little beast like him actually nosing about
in an egg sac and voraciously snapping up all the unfortunate tiny,
red, black-legged baby scale insects. He ate the eggs, too, and seemed
to take some bites at the mother insect herself, and then Mary found
more of the lady-bird beetles, and still more. They were on all the
broom bushes where the white cushions were. And so one of the dreadful
tragedies going on in my garden was soon quite plain to Mary, and she
was very sorry for the helpless white insects.
"Where did the red beetles come from?" she asked pretty soon.
"From Australia," I answered. "Or rather their
great-great-grandparents did. These particular beetles were probably
born right here in the garden, because a colony of them live here.
But they couldn't if there were not some cottony cushion scale insects
here too. For this particular kind of lady-bird beetle can't live on
any other food--at least they don't--except this particular kind of
scale insect and its eggs, which is surely a curious thing, isn't it?"
But Mary is so used to finding that the insects have extremely unusual
and curious habits--that is, habits different from ours--that she
doesn't get excited any more when I tell her about them. She does
though when she finds them out for herself, which makes me wonder if I
haven't wasted a good deal of time in my life giving lectures to
students about things instead of always making them find out for
themselves. And maybe I am wasting some more time now while I am
writing!
"How did they come from Australia?" asks Mary. For she knows that
Australia is several thousand miles away across the ocean from
California, and lady-bird beetles do not swim. At least not from
Australia to America. So I have to give Mary another informing
lecture, and this is it:
"Years and years ago, there lived in some fragrant-leaved orange-trees
in Australia some white cottony cushion insects whose life was
untroubled by other cares than those of eating and of looking after
the children. As each insect was fastened for life on the leaf or twig
that supplied it with all the food it needed, which was simply an
occasional drink of sap, and as the white insects always died before
their children were born, neither of these cares was very harassing.
On thousands of other similar fragrant-leaved orange-trees in
Australia lived millions of other similar white insects. And for a
long time this race of white insects enjoyed life. Those were happy
days. But on a time there came into one of the trees a few small red
beetles, who eagerly and persistently set about the awful business of
eating the defenceless white insects. From this tree the red beetles,
or the children of them, went to other trees where white insects
lived, and with unrelenting rapacity and uncloyed appetite ate all the
white insects they could find. And so in other trees; and finally,
with years, the red beetles had invaded all of the thousands of
fragrant-leaved orange-trees in Australia, and had eaten nearly all of
the millions of white insects.
"One day a very small orange-tree was taken out of the ground in
Australia and sent with many others across the ocean to California. On
this small tree there were a few of the white insects. The little tree
was planted again in California and soon put out many fresh fragrant
leaves. The white insects were astonished and rejoiced that day after
day went by without the appearance of any red beetles. The white
insects increased in numbers; there were thousands of fragrant-leaved
orange-trees in California, and in a few years there were millions of
white insects in them. One morning a man stood among the trees and
said, 'Confound these bugs; they'll ruin me; what shall I do?' and a
man who knew said, 'Get some red beetles from Australia.' So this
orange-grower, with some others, paid a man to go to Australia and
collect some live red beetles. The collector went across the ocean,
three weeks' steady steaming, and sent back a few of the voracious
little beetles in a pill box. They were put into a tree in a
California orange-orchard in which there were many cottony cushion
scale insects. The red insects promptly began eating the white ones;
and their children and grandchildren and great-grandchildren have kept
up this eating ever since. And so the orange-growers never tire of
telling how the red beetles (whose name is Vedalia) were brought from
Australia to save them from ruin by the white insects (whose name is
Icerya)."
Now there are not many cottony cushion scales left in California. A
very promising colony of them seems to have sprung up in my Scotch
broom bushes. But the red beetles have found their way there already,
as Mary and I discovered to-day, and so we think that by the time the
broom flowers come, there will be few white insects left in the
bushes.
[Illustration: THE VENDETTA]