Fig. 289.—Chrysalis of the Vine Pyralis.
The caterpillar of the pyralis ([Fig. 288]) is called, in vulgar parlance, according to the different places in which it occurs, vine worm, summer worm, vintage worm, shell. In the south of France it is called, in the patois of Languedoc, babota. Almost immediately after they leave the eggs, the little caterpillars hide themselves in the fissures of the vine stocks or the props which support them. They spin a small cocoon of a greyish silk, in which they remain curled up till the month of May. From the moment the leaves begin to develop they throw out threads here and there, entangling all the young shoots of the vine, which gives a desolate appearance to the vineyards. The leaves of the vine are their favourite food, but they attack the seeds of the grape also. As they increase in size every day, the damage they do goes on increasing, and has not reached the maximum of intensity till the moment when the caterpillars are about to change into chrysalides. They are then three-quarters of an inch long and of a yellowish green colour.
Fig. 290.—The Vine Pyralis in its three states. 1. Leaf with batches of eggs laid upon it. 2. Batches of recently laid eggs. 3. Eggs in which caterpillars can be perceived. 4. Batch of eggs from which the caterpillars have already emerged. 5. Small caterpillars hanging by threads. 6. Leaf with the chrysalis. 7. Caterpillar. 8. Moth.
From the 20th of June to the 10th of July they seek shelter in the dry and interlaced leaves which have already served them for places of refuge and partly also for food, or else they make themselves a fresh nest.
At the end of two or three days, the caterpillar has become a chrysalis ([Fig. 289]), which in a short time assumes a brown colour. Shut up in the interior of the cocoon which the caterpillar had spun before undergoing its metamorphosis, it changes into a moth at the end of from fourteen to sixteen days.
The best way to diminish the ravages of the pyralis is to pluck off the leaves which are laden with eggs, and burn them, or bury them in deep holes.