276 



SCIENTIFIC NE^A^S. 



[Mar. 23, 1888. 



species, would have remained almost unknown, though 

 they have been used for thousands of years in the Far 

 East. But a disease — or rather two diseases, known as 

 Flacherie and p^brine — broke out in the silk-rearing dis- 

 tricts of France and Lombardy, and threatened Bombyx 

 mori with extinction. Hence manufacturers were com- 

 pelled to seek other sources of supply, and several silk 

 insects of India and China were thus brought into notice. 



Of these, the most important is the Tussur, Antherea 

 tnylitta ; a large moth of a leather-brown colour, 

 having on each wing a transparent spot bordered with a 

 violet ring. The cocoon is three or four times as large 

 as that of the common silk-worm. Moreover, there are 

 two crops every season, whilst of Bombyx mori, 

 there is yearly only one generation. Its chief defect is 

 a brown colour, which appears in patches. This hue is 

 the more decided the richer the food of the insect has 

 been in astringent matter. Tussur caterpillars, fed 

 in Europe on the leaves of the apple-tree, gave a much 

 darker silk than others fed on the foliage of the pear and 

 the plum, which contain less tannin. Major Coussmaker, 

 who has carefully studied the nurture of this species in 

 India, finds that by a proper regulation of their diet for 

 some time before the caterpillars spin up, the cocoons 

 may be obtained perfectly and permanently white. 



Another silk-insect, much esteemed in China, is 

 Attacits atlas, the giant of the group. This insect 

 measures upwards of ten inches in stretch of wing. 

 The caterpillar feeds on the barberry, the sallow, the 

 plum, and apple. The cocoon is of a light umber-brown, 

 from two to three inches in length, and one inch in 

 diameter in the widest part. It weighs about a quarter 

 of an ounce. 



A very interesting species is Antherea Rama-mal, 

 from Japan. The silk is of a beautiful apple-green colour. 

 The moth in question has been introduced into India, 

 and seems likely to yield a very useful silk. 



We have not space to enumerate the various other 

 insects capable of yielding valuable fibres. We must 

 note that although the silkworm disease has been in the 

 main overcome, thanks to the skill of M. Pasteur, the 

 demand for the wild silks is extending. They are used 

 not as substitutes for ordinary silk, but for a number of 

 novel and curious tissues. This industry owes its 

 existence and its future prospects mainly to Mr. Thomas 

 Wardle, of Leek, and Sir S. G. Lister, of Bradford. 



Sparrow Ravages in Cheshire. — In a Manchester 

 daily paper of the 30th ult. is the following suggestive 

 item : — " At the annual meeting of the Cheshire Farmers' 

 Club on Saturday evening, the chairman, Mr. John 

 Roberts, the largest tenant farmer on the Hawarden 

 estate, referred to the habits of the common house- 

 sparrow, and said that the Wirral farmers of Cheshire 

 were paying 6d. per dozen for all sparrows killed, add- 

 ing that some idea of the fecundity of the pest might be 

 formed from the fact that, without appreciably affecting 

 their numbers in the district, no less a sum than 

 _;£i4 15s. 6d. had been recently spent in that way, 

 representing the destruction of 7,192 sparrows. And 

 this money the Cheshire farmers admit has been thrown 

 away, as the sparrows seem to be as numerous as 

 ever. Did these bucolic Gothamites never hear of such 

 a phrase as the " balance of nature " ? Why are th 

 sparrows so numerous ? Simply because, in the interes 

 of game preservers, all the birds of prey have bee 

 nearly extirpated, so that the game preservers may b 



able annually to slaughter a few more partridges and 

 pheasants when the " killing times " come round. 

 Sparrowhawks, comparatively harmless kestrels, and 

 vermin-destroying owls are systematically shot down 

 by the keepers ; also the buzzards and harriers ; and 

 the handsome peregrine has but a short lease of life 

 when he appears on any grouse moor or estate in the 

 lowlands. The farmers not only complain of the loss 

 sustained by sparrows, but about the damage done to 

 their cereal crops, standing and garnered, by rats and 

 mice. Could they not ask their landlords, or the 

 keepers of the latter, to spare the raptorial birds — hawks, 

 buzzards, owls, etc. — which prey largely on small birds, 

 such as sparrows, and on rats and mice ? If nature 

 was allowed her own way, and if the above raptorial 

 birds were not killed off so systematically by gun, trap, 

 and even poison, we should not hear so much of the 

 sparrow pest, or the destructive ravages of rats and 

 mice. In the interests of the game preservers, stoats 

 and weasels — the polecat is now all but extinct — which 

 feed largely on rats and mice, are killed off, that more 

 game may be had for " sport." — Newcastle Daily 

 Observer. 



All this was fully and ably enforced years ago by 

 Charles Waterton. But he preached to deaf ears. The 

 destruction of an owl or of its eggs should be made a 

 misdemeanour. 1 



Ferocity of the Alligator. — The harmless character 

 of the alligator of North America (Alligator Mississippi- 

 ensis) is not recognised by actual observers. A corre- 

 spondent of the Field describes a fight which took place 

 in Florida between an alligator and three bulls. After 

 a desperate struggle two of the bulls and the alligator 

 fell victims, the surviving bull being severely injured. 

 The alligator was only 17ft. in length. We may judge 

 what chance the three bulls would have had against the 

 crocodiles of Borneo and New Guinea, which may reach 

 40ft.- in length, and are more powerfully-built reptiles 

 than the alligators of the western hemisphere. It may 

 be useful to point out the differences between the croco- 

 dile and the alligator, as they are often confounded. 

 The crocodile have a toothed fringe on the hind legs, and 

 the toes are completely webbed. There is a canine 

 tooth in the lower jaw, which is visible externally when 

 the mouth is shut. In the alligators, on the contrary, 

 the hind legs are simply rounded, the feet are not com- 

 pletely webbed, and the canine tooth of the lower jaw 

 is received in a notch in the upper jaw, so as to be con- 

 cealed when the mouth is shut. The crocodiles occupy 

 the rivers of tropical Africa, Asia, and Australia, whilst 

 the alligators are found in America. Some crocodiles, 

 however, have been found in the West Indies, and one 

 species of alligator has been met with in China. 



The Excretory Organs of Spiders. — Dr. J. C. C. 

 Loman {Sijdsk Nederal Dierkimde Fereen) shows that these 

 organs are not homologous in all the Tracheata, and that 

 possibly the Arachnidea and the Crustacea are more nearly 

 related than is admitted in the text-books. 



The Kiwi of New Zealand. — According to a corre- 

 spondent of theNewcaslle Weekly Chronicle, the egg of the 

 kiwi, or Aptcryx, is much larger than that of any other 

 bird of similar size, nearly as large as that of the emu. 

 It is to be regretted that these harmless and curious birds 

 are being wantonly extirpated. 



