The number of the aëronautic spiders occasionally suspended in the atmosphere, says Mr. Murray, I believe to be almost incredible, could we ascertain their amount. I was walking with a friend on the 9th, and noticed that there were four of these insects on his hat, at the moment there were three on my own; and from the rapidity with which they covered its surface with their threads, I cannot doubt that they are chiefly concerned in the production of that tissue which intercepts the dew, and which, illuminated by the morning sun, "glitters with gold, and with rubies and sapphires." Indeed, I have noticed that, when the frequent descent of the aëronautic spider was determined, a newly rolled turnip field was, in a few hours, overspread by a carpet of their threads. It may be remarked that our little aëronaut is very greedy of moisture, though abstemious in other respects. Its food is perhaps peculiar, and only found in the superior regions of the sky. Like the rest of its tribe, it is doubtless carnivorous, and may subserve some highly important purpose in the economy of Providence; such, for instance, as the destruction of that truly formidable, though almost microscopically minute insect, the Fùria infernàlis, whose wounds are stated to be mortal. Its existence has been indeed questioned, but by no means disapproved; that, and some others, injurious to man, or to the inferior creation, may be its destined prey, and thus our little aëronaut, unheeded by the common eye, may subserve an important good. Mr. Bowman, F.L.S. says, "We arrested several of these little aëronauts in their flight, and placed them on the brass gnomon of the sundial, and had the gratification to see them prepare for, and recommence, their aerial voyage. Having crawled about for a short time, to reconnoitre, they turned their abdomens from the current of air, and elevated them almost perpendicularly, supporting themselves solely on the claws of their fore legs, at the same instant shooting out four or five, often six or eight, extremely fine webs, several yards long, which waved in the breeze, diverging from each other like a pencil of rays, and strongly reflecting the sunbeams. After the insects had remained stationary in this apparently unnatural position for about half a minute, they sprang off from the stage with considerable agility, and launched themselves into the air. In a few seconds after they were seen sailing majestically along, without any apparent effort, their legs contracted together, and lying perfectly quiet on their backs, suspended from their silken parachutes, and presenting to the lover of nature a far more interesting spectacle than the balloon of the philosopher. One of these natural aëronauts I followed, which, sailing in the sunbeams, had two distinct and widely diverging fasciculi of webs, and their position in the air was such, that a line uniting them would have been at right angles with the direction of the breeze."--_Mag. Natural History_.