=Spanish Silkworm Gut.=--The business of manufacturing silkworm gut in Spain is a considerable industry. The method of preparation is thus described in the Journal of the Society of Arts: After the silkworm grub has eaten enough mulberry leaves, and before it begins to spin, which is during the months of May and June, it is thrown into vinegar for several hours. The insect is killed and the substance which the grub, if alive, would have spun into a cocoon is drawn out from the dead worm into a much thicker and shorter silken thread, in which operation considerable dexterity and experience are required. Two thick threads from each grub are placed for about four hours in clear cold water, after which they are put for ten or fifteen minutes in a solution of some caustic. This loosens a fine outer skin on the threads, which is removed by the hands, the workman holding the threads in his teeth. The silk is then hung up to dry in a shady place, the sun rendering it brittle. In some parts of the country these silk guts are bleached with sulphur vapor, which makes them beautifully glossy and snow-white, while those naturally dried have a yellowish tint. The quality of the gut is decided according to the healthy condition of the worm, round indicating a good quality and flat an inferior one. =The Nests of Burrowing Bees.=--Prof. John B. Smith, having explained to his section of the American Association a method which has been successfully applied, of taking casts in plaster of Paris of the homes of burrowing insects, with their branchings, to the depth of six feet, described some of the results of its application. Bees, of the genus _Calletes_, dig vertically to the depth of eighteen inches or more, then burrow horizontally from two to five inches farther, and construct a thin, parchmentlike cell of saliva, in which the egg is deposited, with pollen and honey for the food of the larva. They then start a new horizontal burrow a little distance from the first, and perhaps a third, but no more. The vertical tubes are then filled up, so that when the bees come to life they must burrow from six to twenty-four inches before they can reach the surface. Another genus makes a twisted burrow; another makes a vertical burrow that may be six feet deep. About a foot below the surface it sends off a lateral branch, and in this it excavates a chamber from one to two and a half inches in diameter. Tubes are sent down from this chamber, as many perhaps as from six to twenty together, and these are lined with clay to make them water-tight. This bee, when it begins its burrow, makes an oblique gallery from four to six inches long before it starts in the vertical direction, and all the dirt is carried through this oblique gallery. Then the insect continues the tube vertically upward to just below the surface, and makes a small concealed opening to it here, taking care to pile no sand near it. This is the regular entrance to the burrow. MINOR PARAGRAPHS.