SILKWORM s made of a dry, inelastic, silvery gray silk, d of a very elastic, viscid yellow silk ; the rmer is the supporting radiating framework, and the latter forms the concentric entangling circles. It sucks out the gum of its old web for making a new one ; this is a circle minus its upper sextant, consisting of a continuous spiral viscid line laid upon the numer- ous radii. The spider remains quiet in its web, head downward, and is very active upon it when a fly is entangled ; it is slow on the ground, and likes the full glare of the sun. The web is never vertical, but in- Spider, Male and Female, one $$& ^ T" half the natural size. gle of 70 ; when it is touched, it
- es its web violently. Like most if not all
metric spiders, though well provided with es, it can distinguish only light ; if the in-
- t caught happens to be on a radius beyond
r reach, she cannot see it, and returns to the >ntre to shake the web and ascertain what dius holds the weight ; two spiders will often 'proach each other till their legs interlock fore they are aware of their proximity, earing and touch are acute. The males are ly a quarter of an inch long, with the legs reading laterally and longitudinally about ree fourths of an inch ; the body and legs dark brown ; they make no webs, unless hen very young, and seem to hang on to that some female, or to some part of her body, f. "Wilder had an idea that the silk of this ider might be useful in the arts, and devised veral ingenious ways to procure it. He found at from one pair of spinners came white and m another yellow silk, which he was enabled wind separately by a simple machine to the teat of nearly two miles, at 170 revolutions minute, in less than five hours of winding he could not reel more than 300 yards one time ; the diameter varied from -p^Vo" ToVo" of an inch, and its strength was very eat. For details see the " Popular Science
- onthly " for April, 1875.
SILKWORM, the larva of a lepidopterous in- sect of the moth division, family ~bom~bycidce, and genus lombyx (Schrank). Of all the silk- producing larvae, that of the common silkworm (B. mori, Schr.) is the most important, as from it is obtained all the European and most of the Chinese silk. The moth is about an inch long and 2 in. in alar extent, of a whitish or pale yellowish color, with two or three ob- t streaks and a lunate spot on the upper
wings ; the trunk is very short ; the superior wings decumbent, and the inferior extending almost horizontally beyond them; the anten- Larva, Pupa, Cocoon, and Moth of Eombyx mori. na3 of the males are pectinated ; the males fly swiftly in the evening and sometimes by day, but the females are inactive ; the latter live but a few hours after the eggs are deposited on the mulberry trees. The eggs are about the size of mustard seeds, and the young emerge in a few days if the weather or air of the breeding room is warm and dry ; when first hatched they are one or two lines long, of a dark color, and very soon begin to eat vora- ciously, with short intervals of abstinence du- ring the moultings, until full grown, when they are about 3 in. long, light green with darker marks, with blackish head, and fleshy protuber- ance on the last joint but one ; there are 12 segments to the body, 9 stigmata or breathing Silkworm Moth, Male. holes on each side, and 16 legs, of which the anterior 6 are hooked, and the others, inclu- ding the 2 on the last segment, end in disks ;
