THE CABBAGE MILLER
"_And here and yonder a flaky butterfly
Was doubting in the air._"
--MCDONALD.
With the first approach of spring comes swarms of large green flies
which bask in the March sun on the south sides of buildings. They are
not with us long, however, until we notice flashes of white quickly
moving about from one early weed to another. These are the advance
guards of the cabbage millers or butterflies. All through the cold
winter they remained in the chrysalis stage stuck to the sides of
houses, fence posts and in other protected places, awaiting the first
breath of spring. The first adults to emerge find no cabbage on which
to lay their eggs so they are compelled to use other plants such as
pepper grass.
[Illustration: Egg of cabbage miller much enlarged.]
The eggs are very small and are usually placed on the lower edge of the
leaf. These hatch and the small green worms appear. Throughout the
summer there are a number of broods produced and an enormous amount of
damage is done. Just before frost the last caterpillars search for
protected places where they pass to the pupal or resting stage for the
winter. No cocoon is spun by this caterpillar.
Where measures are not taken to control the cabbage worms they destroy
much of the cabbage crop each season. The white butterflies can be seen
any day during the summer visiting cabbage, mustard, radishes and other
similar plants. By destroying all of the worms and millers in the early
spring one has less trouble later. This can be done by hand picking, or
where the patch is large by spraying with a poison solution to which
soap is added to keep the solution from rolling off in large drops.
Poison can be used until the heads are well formed, but if the first
worms in the spring are destroyed, later spraying is unnecessary though
an occasional handpicking will help.
OBSERVATIONS AND STUDY
[Illustration: Cabbage worm feeding, slightly enlarged.]
Go into the garden and examine the cabbage for small green worms which
vary from one fourth to a little over an inch in length. What is the
nature of their work on the leaf? Where do they feed most, on the outer
or inner leaves? Do they eat the entire leaf? How does the work of the
young worms differ from that of the larger ones? Do they spin silk? Are
they on the top or under side of the leaf? Examine under the dead and
dried leaves at the ground and see if you can find small, hard, gray
objects which have sharp angles and which are tied to the leaf with a
cord of silk. What are these objects? Watch the miller as she visits the
cabbage and see if you can find the small eggs which she lays on the
under side of the leaves. When she visits a cabbage plant she bends her
body up under the outer leaves and stops but a moment, fluttering all
the while as she sticks the small egg to the leaf. It is about the size
of a small crumb of bread. What does the miller feed on? Does she visit
flowers? If so, what flowers?
[Illustration: Pupa or chrysalis of cabbage miller.]
BREEDING WORK
Collect a few of the worms and put them in a glass jar with a piece of
cabbage leaf. Examine them carefully and watch them crawl. How many legs
do they have? Where are they placed on the body? How can they use so
many legs while crawling? How many joints are there to the body? Note
the short fine hair all over the body which gives it the appearance of
green velvet. What color is the head? How does the caterpillar feed?
Write a brief description of the worm. Do not mistake it for the cabbage
span-worm which is also green, but which walks by humping up its back.
[Illustration: Cabbage miller on red clover blossom.]
Keep the cabbage worms in the jar for a few days and watch them
disappear. After they have disappeared, what is left in the jar? These
are the chrysalids or pupae of the insect and later from them will come
the millers. Take one of the pupae in your hand and see if it can move.
If it is in the summer the miller will appear in a week, but if it is in
the late fall it will simply pass the winter in the pupa stage. Watch
the miller escape from the pupal case and describe it. Examine the
miller carefully and describe briefly the number of legs, wings,
segments of body, sucking tube and color markings. Make careful drawings
of the caterpillar, chrysalis and butterfly. What gives the color to the
wings? Rub the wings between your fingers and see if the color comes
off. The wings are covered with very small scales of different colors
which combine to give the beautiful markings. The wings of all
butterflies and moths are covered with scales and hairs in this way. In
this insect we find both chewing and sucking mouth parts. The
caterpillar chews while the parent butterfly has a long tube for sucking
up nectar from flowers and water from puddles in the road.
* * * * *
"_Far out at sea--the sun was high,
While veered the wind and flapped the sail;
We saw a snow-white butterfly
Dancing before the fitful gale
Far out at sea._
"_The little wanderer, who had lost
His way, of danger nothing knew;
Settled a while upon the mast;
Then fluttered o'er the waters blue
Far out at sea._
"_Above, there gleamed the boundless sky;
Beneath, the boundless ocean sheen;
Between them danced the butterfly,
The spirit-life of this vast scene,
Far out at sea._
"_The tiny soul that soared away,
Seeking the clouds on fragile wings,
Lured by the brighter, purer ray
Which hope's ecstatic morning brings--
Far out at sea._
"_Away he sped, with shimmering glee,
Scarce seen, now lost, yet onward borne!
Night comes with wind and rain, and he
No more will dance before the morn,
Far out at sea._
"_He dies, unlike his mates, I ween
Perhaps not sooner or worse crossed;
And he hath felt and known and seen
A larger life and hope, though lost
Far out at sea._"
--R. H. HORNE.