SOME NEW FOUND FRIENDS.
In the second number of the current volume of the Canadian Entomologist is a very interesting account of the discovery of some small creatures that feed on the eggs of the Tent Caterpillars. It is very gratifying indeed to the orchardist, to learn that he has help from any quarter in the work of destroying such pests as these. During the past summer, the Forest Tent Caterpillar swept over large tracts of country in the Counties of Perth and Middlesex, stripping the leaves from the trees in the orchards, as well as from those in the forest, and doing a vast amount of injury. The question was asked at the Summer meeting in Stratford, if this pest was likely to continue in such force in years to come; if so, the out-look for fruit in those parts was gloomy enough. It was bad enough to have to look after the common Tent Caterpillar, and keep that in subjection, but such an invasion of its congener, if likely to be continuous, was fearful to contemplate. The discovery, to which reference is now made, may help to answer the question, and to illustrate the wonderful measures adopted to keep in check all undue multiplication of our insect enemies, and so to preserve the balance of power.
The distinguished editor of the Entomologist was devoting an evening to the microscopic examination of some cluster of eggs of both the American and the Forest Tent Caterpillar, when he noticed that in many instances the gummy covering of the clusters was imperfect; that, here and there, a piece had disappeared, leaving the eggs bare, and in some cases the exposed eggs were empty. This circumstance induced him to cut into the affected clusters, which were found to be colonized by mites. They had evidently eaten into the eggs and devoured the young larvæ, and also consumed the missing patches of the glutinous covering. In some of the eggs the larvæ were found uninjured, while out of others would proceed several active little mites. Sometimes these mites were so small that five or more were found in a single egg-shell, with plenty of room and to spare. These, which he noticed were very active and nearly transparent, were doubtless young mites, not fully grown. The full grown mites were much larger, one of them nearly filling the egg-shell; these were of a pale-red color, with bright red eyes, and sluggish in their movements. On the outside of some of these egg-clusters, he found tiny pale-red eggs, which proved to be the eggs of these mites. On nearly every cluster that he examined, he found more or less of these mites. It is to be hoped that they are generally distributed over those parts of the country that have been infested by these Tent Caterpillars, if they are, they will help vastly in checking their undue multiplication.
As some of our readers may feel desirous of examining the egg-clusters of these Tent Caterpillars for themselves, we give an engraving, shewing the cluster as it will now be found, fastened around the twigs of the apple trees. They will be more easily seen in a cloudy day, and will be found near the ends of the shoots, not often more than a foot from the tip, and frequently but an inch or two. The gummy covering will prevent the individual eggs from being seen quite as distinctly as they are shewn in the engraving, it having been removed to shew the regularity of their position. This engraving represents the moth and egg-cluster of the Forest Tent Caterpillar. Fig. a shews a twig with the bracelet of eggs upon it, and b represents the moth with the wings expanded.
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