1882.] 



THE LANCASTER FARMER. 



119 



will be found to spring from . pale-colored 

 tubercles. Different sluides of dark gray will, 

 however, be fouud anioiig worms balcliinj,' 

 from the same batch of eggs. The hairs and 

 tubercles are not nolicealjle after tlie first 

 molt and the worm gradually gets ligiiter and 

 lighter, until, in the last stage, it is of a 

 cream-white color. It never becomes entirely 

 smooth, however, as there are short hairs 

 along the sides, and very minute ones, not 

 noticeable with tlie unaided eye, all over the 

 body. 



The preparation for each molt requires from 

 two to three days of fasting and rest, during 

 which time the worm attaches itself finiily by 

 the abdominal prologs (the 8 non-articulated 

 legs under the 6th, 7th, 8th and 9th segments 

 of the body, called prologs in contradistinction 

 to the articulated true legs under the 1st, 

 2nd and 3rd segments,) and holds up the 

 forepart of tlie body, and sometimes the tail. 

 In front of the first joint a dark triangular 

 spot is at this time noticeable, indicating 

 the growth of the new head; and when the 

 term of "sickness" is over, the worm casts its 

 old integument, rests a short time to recover 

 strength, and tlieu, fresliened, supple, and 

 hungry, goes to work feeding voraciously to 

 compensate for lost time. This so-called 

 "sickness" which preceded the molt, was in 

 its turn preceded by a most voracious app?tite 

 which served to stretch the skin. In the 

 operation of molting the new head is first dis- 

 engaged from the old skin, which is then 

 gradually worked back from segment to seg- 

 ment until entirely cast off. If the worm is 

 feeble, or has met with any misfortune, the 

 shriveled skin may remain on the end of the 

 body, being held by the anal horn; in which 

 case the individual usually perishes in the 

 course of time. It has been usually estimated 

 that tlie worm in its growth consumes its own 

 weight of leaves every day it feeds; but this is 

 only an approximation. Yet it is certain that 

 during the last few days before commencing 

 to spin, it consumes more than during the 

 whole of its previous worm existence. It is a 

 curious fact, first noted by Quatrefages, that 

 the color of the abdominal prolegs at this 

 time corresponds with the color of the silk. 



Having attained full growth, the worm is 

 ready to spin up. It shrinks somewhat in 

 size, voids most of the excrement remaining 

 in the alimentary canal; acquires a clear, 

 translucent, often pinkish or amber-colored 

 hue; becomes restless; ceases to feed and 

 throws out silken threads. The silk is elab- 

 orated in a fluid condition in two long, slender 

 convoluted vessels, one upon each side of the 

 alimentary canal. As tb.ese vessels approach 

 the head they become less convoluted and 

 more slender, and finally unite within the 

 spinneret, from which the silk issues in a glu- 

 tinous state and apparently in a single thread. 

 The glutinous liquid which combines the two, 

 and which hardens immediately on exposure 

 to the air, may, however, be dissolved in 

 warm water. The worm usually consumes 

 from three to five days in the construction of 

 the cocoon and then passes in three days 

 moi-e, by a final moft, into the chrysalis state. 



The Cocoon. — The cocoon consists of an 

 outer lining of loose silk known as " floss,'" 

 which is used for carding, and is spun by the 

 worm iu first getting its bearings. The 



amount of this loose silk varies in different 

 breeds. The inner cocoon is tough, strong, 

 and compact, composed of a firm, continuous 

 thread, which is, however, not wound in 

 concentric circles as might be supposed, but 

 irregularly, in short figure of eight loops, first 

 in one place and then in another, so that in 

 reeling, several yards of silk may be taken off 

 without tiie cocoon turning around. In form 

 the cocoon is usually oval, and in color yellow- 

 isli, but ill both these features it varies greatly, 

 being either pure silvery white, cream or car- 

 neous, green, and even roseate, and very often 

 constricted in the middle. It has always 

 been considered possible to distinguish the 

 sex of the contained insect from llie general 

 sfiape of the cocoon, those containing males 

 being slender, depressed in the middle, and 

 pointed at both ends, while the female cocoons 

 are of a smaller size and rounder form, and 

 resemble in shape a hen's egg with equal ends. 

 Mr. Crozier, however, emphatically denies 

 this, and thinks it "next to impossible for 

 the smartest connoisseur not to be mistaken." 



The Cuutsahs. — The chrysalis is a brown, 

 oval body, considerably less in size than the 

 full-grown worm. In the external integument 

 may be traceed folds corresponding with the 

 abdominal rings, the wings folded over the 

 breast, the antennse and the eyes of the in- 

 closed insect — the future moth. At the pos- 

 terior end of the chrysalis, pushed closely up 

 to the wall of the cocoon, is tlie last larval 

 skin, compressed into a dry wad of wrinkled 

 integument. The chysalis state continues for 

 from two to three weeks, when the skin bursts 

 and the moth emerges. 



The Moth. — With no jaws, and confined 

 within tlie narrow space of the cocoon, the 

 moth finds some difficulty In escaping. For 

 this purpose it is provided, in two glands near 

 the obsolete mouth, with a strongly alkaline 

 liquid secretion with which it moistens the 

 end of the cocoon and dissolves the hard 

 gummy lining. Then by a forward and back- 

 ward motion, the prisoner, with crimped and 

 damp wings, gradually forces its way out, 

 and when once out the wings soon expand and 

 dry. The silken threads are simply pushed 

 aside, but enough of thera get broken in the 

 process to renderjthe cocoons from which the 

 moths escape, comparatively useless for reel- 

 ing. Tlie moth is of a cream color, with more 

 or less distinct brownish markings across the 

 wings. The males have broader antennce or 

 feelers than the females, and may by this fea- 

 ture at once be distinguished. Neitlier sex 

 flics, but the male is more active than the 

 female. They couple soon after issuing, and 

 in a short time the female begins depositing 

 her eggs, whether they have been impregnated 

 or not. Very rarely the unimpregnated egg 

 has been obsereed to develop. 



Enemies and Diseases. 



As regards the enemies of the silkworm but 

 little need to be said. It has been generally 

 supposed that no true parasite will attack it, 

 but in China and Japan great numbers of the 

 worms are killed by a disease known as "uji," 

 which is undoubtedly produced by the larva 

 of some insect parasite. Several diseases of a 

 fungoid or epizootic nature, and several mala- 

 dies which have not been sufliciently charac- 

 terized to enable us to determine their nature 

 are common to this worm. One of these dis- 



eases, called mitscardine, has been more or 

 less destructive in Europe for many years. It 

 is of precisely the same nature as the fungus 

 {Eiiqjtisa niKscoe,) which so frequently kills the 

 common house-fly. and which slieds a halo of 

 spores, readily seen upon the window-pane, 

 around its victim. 



A worm, about to die of this disease, be- 

 comes languid, and the pulsations of the dorsal 

 vessel of the heart becomes insensible. It sud- 

 denly dies, and in a few hours becomes stiff 

 rigid and discolori'd; and finally, in about a 

 day, a white powder or efliorescence manifests 

 itself, and soon entirely covers the body, de- 

 veloping most rapidly in a warm, humid, at- 

 mospliere. No outward signs indicate the 

 first stage of the disease, and though it at- 

 tacks worms of all aL'es, it is by far the most 

 fatal in the fifth or last stage, just before the 

 transformation. 



"This disease was proved by Bassi to be 

 due to the development of a fungus (Bolrytis 

 Jiassiana) in the body of the worm. It is cer- 

 tainly iiifcclious, the spores, when they come 

 in contact with the body of the worm, ger- 

 minating and sending forth filaments which 

 penetrate the skin, and, upon reaching the 

 internal i)arts, give off minute floating cor- 

 puscles which eventually spore in the efflor- 

 escent manner described. Yet most silkworm 

 raisers, including such good authorities as P. 

 E. Gueriii-Meneville and Eugene Roberts, 

 (Guide a I'elevcur de vers a sole,) who at first 

 implicitly believed in the fungus origin ofthis 

 disease, now consider that the Botrytis is only 

 the ultimate symptom — the termination of it. 

 At the same time they freely admit that the 

 disease may be contracted by the Botrytis 

 spores coming in contact with worms predis- 

 posed t)y unfavorable conditions to their influ- 

 ence. Such a view implies the contradictory 

 belief that the disease may or may not be the 

 result of the fungus, and those who consider 

 the fungus as the sole cause certainly have 

 the advantage of consistency." Dr. Carpen- 

 ter, an eminent microscopist, believes the fun- 

 gus origin of the disease, and thinks it en- 

 tirely caused by floating spores being carried 

 in at the spiracles or breathing-orifices of the 

 worm, and germinating in the interior of the 

 body. 



Wliichever view be held, it appears very 

 clear that no remedies are known, but that 

 care in producing good eggs, care in rearing 

 the worms, good leaves, pure, even-temper- 

 ed atmosphere, and cleanliness are checks to 

 the disease. The drawers, and other objects 

 with which the diseased worms may have 

 been in contact, should be purified by fumi- 

 gations of sulphurous acid (S. 02), produced 

 by mixing bisulphite of soda with any strong 

 acid, or, better still, by subjecting them to a 

 carbolic-acid spray from an atomizer. In 

 this way all fungus spores will be destroyed. 

 In fact it will be well to wash off the trays or 

 shelves once in a while with diluted carbolic 

 acid, as a sure preventive. It is the best dis- 

 infectant known to science. The cheapest 

 kinds may be used with the same efficacy as 

 the more expensive. 



Another disease known as iiebrine, has 

 proved extremely fatal in Southern Europe, 

 and for twenty years has almost paralyzed 

 silk culture in Fiance. It is a disease which, 

 iu its nature and action, except in being here- 



