Page:Popular Science Monthly Volume 21.djvu/145

Rh broods of the fly are produced in a year, the first laying its eggs in April and May, the second in August and September. The dam age is done by the larva, which lies at the sheathing base of the leaves first above the roots, at or near the surface of the soil, and absorbs the sap from the stalks. From the larva, the insect passes into the pupa state, in which it resembles a flaxseed, and remains in it for the five winter months. The pest flourishes best in rather warm and moist seasons; and it has been noticed that the years when it has been most abundant have been characterized by weather answering to that description. It is afflicted by several parasites by which it is said that nine tenths of every generation of the insects are destroyed. The principal parasites are a chalcid fly that destroys the pupa, and a platygaster, which lays its eggs in the egg. Professor Packard recommends, as remedies for the insect, late sowing of fall wheat, so that the flies may be killed by frost before laying their eggs, high culture to give the plant new vigor, the sowing of the most vigorous and many-stooled varieties, and pasturing, which destroys the "flaxseeds," but is "a rather rude, uncertain remedy." Special remedies like limeing, dusting, burning stubble, etc., are not recommended, because they are inferior to those just mentioned, and are as likely to destroy the helpful parasites as the harmful flies. A comparison of the periods when the flies have been most abundant indicates that the plague has culminating periods in the neighborhood of twenty-five years apart.

Folk-Lore of the Mammoth.—Baron Nordenskiöld, in his "Voyage of the Vega," gives some interesting citations of the folk-lore of the Siberian natives respecting the mammoth, whose remains are very abundant in the country. Evert Yssbrants Ides, a Russian ambassador in 1692, related that the heathen Yakuts, Tunguses, and Ostiaks, supposed that the mammoth always lived in. the earth and went about in it, however hard the ground might be frozen, and that it died when it came so far up that it saw or smelled the air. J. B. Müller, in 1720, added that the tusks were believed to have formed the animal's horns, that they were fastened above the eyes and were movable, and that with them the animal dug a way for itself through the mud; when it came to a sandy soil, the sand ran together so that the mammoth stuck fast and perished. Müller further stated that many natives assured him that they themselves had seen such animals in large grottoes in the Ural Mountains. Klaproth says that the Chinese at Kiakhta considered mammoth ivory the tusks of the giant rat, tien-shu, which is found only in the cold regions along the coast of the Polar Sea, avoids the light, and lives in dark holes in the interior of the earth. Some of the literati believed that the discovery of these immense earth-rats might even explain the origin of earth-quakes. The horns and crania of the rhinoceros, which were found along with the remains of the mammoth, were believed to have belonged to gigantic birds, concerning which stories were related analogous to those told of the roc in the "Arabian Nights." Pieces of the horns were used to increase the elasticity of bows, and were believed to exert a beneficial effect on the arrow, and to tend to make it hit the mark. Ermann and Middledorf suppose that the finds of these remains two thousand years ago gave occasion to Herodotus's account of the Arimaspi and the gold-guarding dragons. Certain it is that during the middle ages such "grip-claws" were preserved as of great value in the treasuries and art collections of the time, and that they gave rise to many a romantic story in the folk-lore, both of the West and the East. Even in our own century, Hedenstrom, in 1830, otherwise an intelligent traveler, believed that the fossil rhinoceros-horns were actual "grip-claws."

Water-Temperatures at the Top and Bottom of Lakes.—Professor William Ripley Nichols has obtained, from the examination of the relative temperatures of the surface and the depths of fresh-water ponds near Boston, Massachusetts, results that differ from the views on this subject that are commonly held and taught. In Fresh Pond and Mystic Pond considerable difference was shown to exist in the temperature at the top and at the bottom, and the temperature appeared to decrease regularly from top to bottom. Having compared his own observations with those made in Swiss and