Adult stage.—I can find no account of any constant difference in the moths of the most distinct races. Mrs. Whitby assured me that there was none in the several kinds bred by her; and I have received a similar statement from the eminent naturalist, M. de Quatrefages. Captain Hutton also says[76] that the moths of all kinds vary much in colour, but in nearly the same inconstant manner. Considering how much the cocoons in the several races differ, this fact is of interest, and may probably be accounted for on the same principle as the fluctuating variability of colour in the caterpillar, namely, that there has been no motive for selecting and perpetuating any particular variation.
The males of the wild Bombycidæ “fly swiftly in the day-time and evening, but the females are usually very sluggish and inactive.”[77] In several moths of this family the females have abortive wings, but no instance is known of the males being incapable of flight, for in this case the species could hardly have been perpetuated. In the silk-moth both sexes have imperfect, crumpled wings, and are incapable of flight; but still there is a trace of the characteristic difference in the two sexes; for though, on comparing a number of males and females, I could detect no difference in the development of their wings, yet I was assured by Mrs. Whitby that the males of the moths bred by her used their wings more than the females, and could flutter downwards, though never upwards. She also states that, when the females first emerge from the cocoon, their wings are less expanded than those of the male. The degree of imperfection, however, in the wings varies much in different races and under different circumstances. M. Quatrefages[78] says that he has seen a number of moths with their wings reduced to a third, fourth, or tenth part of their normal dimensions, and even to mere short straight stumps: “il me semble qu’il y a là un véritable arrêt de développement partiel.” On the other hand, he describes the female moths of the André Jean breed as having “leurs ailes larges et étalées. Un seul présente quelques courbures irrégulières et des plis anormaux.” As moths and butterflies of all kinds reared from wild caterpillars under confinement often have crippled wings, the same cause, whatever it may be, has probably acted on silk-moths, but the disuse of their wings during so many generations has, it may be suspected, likewise come into play.
The moths of many breeds fail to glue their eggs to the surface on which they are laid,[79] but this proceeds, according to Capt. Hutton,[80] merely from the glands of the ovipositor being weakened.
As with other long-domesticated animals, the instincts of the silk-moth have suffered. The caterpillars, when placed on a mulberry-tree, often commit the strange mistake of devouring the base of the leaf on which they are feeding, and consequently fall down; but they are capable, according to M. Robinet,[81] of again crawling up the trunk. Even this capacity sometimes fails, for M. Martins[82] placed some caterpillars on a tree, and those which fell were not able to remount and perished of hunger; they were even incapable of passing from leaf to leaf.
Some of the modifications which the silk-moth has undergone stand in correlation with one another. Thus, the eggs of the moths which produce white cocoons and of those which produce yellow cocoons differ slightly in tint. The abdominal feet, also, of the caterpillars which yield white cocoons are always white, whilst those which give yellow cocoons are invariably yellow.[83] We have seen that the caterpillars with dark tiger-like stripes produce moths which are more darkly shaded than other moths. It seems well established[84] that in France the caterpillars of the races which produce white silk, and certain black caterpillars, have resisted, better than other races, the disease which has recently devastated the silk-districts. Lastly, the races differ constitutionally, for some do not succeed so well under a temperate climate as others; and a damp soil does not equally injure all the races.[85]
From these various facts we learn that silk-moths, like the higher animals, vary greatly under long-continued domestication. We learn also the more important fact that variations may occur at various periods of life, and be inherited at a corresponding period. And finally we see that insects are amenable to the great principle of Selection.
REFERENCES
[1] ‘Poultry Chronicle,’ 1854, vol. ii. p. 91 and vol. i. p. 330.
[2] Dr. Turral, ‘Bull. Soc. d’Acclimat.,’ tom. vii., 1860, p. 541.
[3] Willughby’s ‘Ornithology,’ by Ray, p. 381. This breed is also figured by Albin in 1734 in his ‘Nat. Hist. of Birds,’ vol. ii. p. 86.
[4] F. Cuvier, in ‘Annales du Muséum,’ tom. ix. p. 128, says that moulting and incubation alone stops these ducks laying. Mr. B. P. Brent makes a similar remark in the ‘Poultry Chronicle,’ 1855, vol. iii. p. 512.
[5] Rev. E. S. Dixon, ‘Ornamental and Domestic Poultry’ (1848), p. 117. Mr. B. P. Brent, in ‘Poultry Chronicle,’ vol. iii., 1855, p. 512.
[6] Crawfurd on the ‘Relation of Domesticated Animals to Civilisation,’ read before the Brit. Assoc. at Oxford, 1860.
[7] Dureau de La Malle, in ‘Annales des Sciences Nat.,’ tom. xvii. p. 164; and tom. xxi. p. 55. Rev. E. S. Dixon, ‘Ornamental Poultry,’ p. 118. Tame ducks were not known in Aristotle’s time, as remarked by Volz, in his ‘Beiträge zur Kulturgeschichte,’ 1852, s. 78.
[8] I quote this account from ‘Die Enten-und Schwanenzucht,’ Ulm 1828, s. 143. See Audubon’s ‘Ornithological Biography,’ vol. iii. p. 168, on the taming of ducks on the Mississippi. For the same fact in England, see Mr. Waterton in Loudon’s ‘Mag. of Nat. Hist.,’ vol. viii. 1835, p. 542; and Mr. St. John, ‘Wild Sports and Nat. Hist. of the Highlands,’ 1846, p. 129.
[9] Mr. E. Hewitt, in ‘Journal of Horticulture,’ 1862, p. 773; and 1863, p. 39.
[10] I have met with several statements on the fertility of the several breeds when crossed. Mr. Yarrell assured me that Call and common ducks are perfectly fertile together. I crossed Hook-billed and common ducks, and a Penguin and Labrador, and the crossed Ducks were quite fertile, though they were not bred inter se, so that the experiment was not fully tried. Some half-bred Penguins and Labradors were again crossed with Penguins, and subsequently bred by me inter se, and they were extremely fertile.
[11] ‘Poultry Chronicle,’ 1855, vol. iii. p. 512.
[12] ‘Journal of the Indian Archipelago,’ vol. v. p. 334.
[13] ‘The Zoologist,’ vols. vii, viii. (1849-1850), p. 2353.
[14] ‘Poultry Chronicle,’ 1855, vol. iii. p. 512.
[15] ‘Poultry Chronicle,’ vol. iii. 1855, p. 312. With respect to Rouens see ditto vol. i. 1854, p. 167.
[16] Col. Hawker’s ‘Instructions to young Sportsmen,’ quoted by Mr. Dixon in his ‘Ornamental Poultry,’ p. 125.
[17] ‘Cottage Gardener,’ April 9th, 1861.
[18] These hybrids have been described by M. Selys-Longchamps in the ‘Bulletins (tom. xii. No 10) Acad. Roy. de Bruxelles.’
[19] ‘Proc. Zoolog. Soc.,’ 1861, p. 261.
[20] ‘Ceylon,’ by Sir J. E. Tennent, 1859, vol. i. p. 485; also J. Crawfurd on the ‘Relation of Domest. Animals to Civilisation,’ read before Brit. Assoc. 1860. See also ‘Ornamental Poultry,’ by Rev. E. S. Dixon, 1848, p. 132. The goose figured on the Egyptian monuments seems to have been the Red goose of Egypt.
[21] Macgillivray’s ‘British Birds,’ vol. iv. p. 593.
[22] Mr. A. Strickland (‘Annals and Mag. of Nat. Hist.,’ 3rd series, vol. iii. 1859, p. 122) reared some young wild geese, and found them in habits and in all characters identical with the domestic goose.
[23] See also Hunter’s ‘Essays,’ edited by Owen, vol. ii. p. 322.
[24] Yarrell’s ‘British Birds,’ vol. iii. p. 142.
[25] L. Lloyd, ‘Scandinavian Adventures,’ 1854, vol. ii. p. 413, says that the wild goose lays from five to eight eggs, which is a much fewer number than that laid by our domestic goose.
[26] The Rev. L. Jenyns (Blomefield) seems first to have made this observation in his ‘British Animals.’ See also Yarrell, and Dixon in his ‘Ornamental Poultry’ (p. 139), and ‘Gardener’s Chronicle,’ 1857, p. 45.
[27] Mr. Bartlet exhibited the head and neck of a bird thus characterised before the Zoological Soc., Feb. 1860.
[28] W. Thompson, ‘Natural Hist. of Ireland,’ 1851, vol. iii. p. 31. The Rev. E. S. Dixon gave me some information on the varying colour of the beak and legs.
[29] Mr. A. Strickland, in ‘Annals and Mag. of Nat. Hist.,’ 3rd series, vol. iii., 1859, p. 122.
[30] ‘Poultry Chronicle,’ vol. i., 1854, p. 498; vol. iii. p. 210.
[31] ‘The Cottage Gardener.’ Sept. 4th, 1860, p. 348.
[32] ‘L’Hist. de la Nature des Oiseaux,’ par P. Belon, 1555, p. 156. With respect to the livers of white geese being preferred by the Romans see Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ tom. iii. p. 58.
[33] Mr. Sclater on the black-shouldered peacock of Latham, ‘Proc. Zoolog. Soc.,’ April 24th, 1860. Mr. Swinhoe at one time believed, (‘Ibis,’ July, 1868) that this kind of peafowl was found wild in Cochin China, but he has since informed me that he feels very doubtful on this head.
[34] ‘Proc. Zoolog. Soc.,’ April 14th, 1835.
[35] ‘The Field,’ May 6th, 1871. I am much indebted to Mr. Canning for information with respect to his birds.
[36] ‘Proc. Zoolog. Soc.,’ April 8th, 1856, p. 61. Prof. Baird believes (as quoted in Tegetmeier’s ‘Poultry Book,’ 1866, p. 269) that our turkeys are descended from a West Indian species now extinct. But besides the improbability of a bird having long ago become extinct in these large and luxuriant islands, it appears (as we shall presently see) that the turkey degenerates in India, and this fact indicates that it was not aboriginally an inhabitant of the lowlands of the tropics.
[37] Audubon’s ‘Ornithological Biography,’ vol. i., 1831, pp. 4-13; and ‘Naturalist’s Library,’ vol. xiv., Birds, p. 138.
[38] F. Michaux, ‘Travels in N. America,’ 1802, Eng. translat., p. 217.
[39] ‘Ornamental Poetry,’ by the Rev. E. S. Dixon, 1848, p. 34.
[40] Bechstein, ‘Naturgesch. Deutschlands,’ B. iii., 1793, s. 309.
[41] Mr. Bartlett in ‘Land and Water,’ Oct. 31st, 1868, p. 233; and Mr. Tegetmeier in the ‘Field,’ July 17th, 1869, p. 46.
[42] ‘Gardener’s Chronicle,’ 1852, p. 699.
[43] E. Blyth, in ‘Annals and Mag. of Nat. Hist.,’ 1847, vol. xx. p. 391.
[44] Roulin makes this remark in ‘Mém. de divers Savans, l’Acad. des Sciences,’ tom. vi., 1835, p. 349. Mr. Hill, of Spanish Town, in a letter to me, describes five varieties of the Guinea fowl in Jamaica. I have seen singular pale-coloured varieties imported from Barbadoes and Demerara.
[45] For St. Domingo, see M. A. Salle, in ‘Proc. Zoolog. Soc.’ 1857, p. 236. Mr. Hill remarks to me, in his letter, on the colour of the legs of the feral birds in Jamaica.
[46] Mr. B. P. Brent, ‘The Canary, British Finches,’ etc., pp. 21, 30.
[47] ‘Cottage Gardener,’ Dec. 11th, 1855, p. 184: an account is here given of all the varieties. For many measurements of the wild birds, see Mr. E. Vernon Harcourt, ibid., Dec. 25th, 1855, p. 223.
[48] Bechstein, ‘Naturgesch. der Stubenvögel,’ 1840, s. 243; see s. 252 on the inherited song of Canary-birds. With respect to their baldness see also W. Kidd’s ‘Treatise on Song-Birds.’
[49] W. Kidd’s ‘Treatise on Song-Birds,’ p. 18.
[50] The ‘Indian Field,’ 1858, p. 255.
[51] Yarrell’s ‘British Fishes,’ vol. i. p. 319.
[52] Mr. Blyth in the ‘Indian Field,’ 1858, p. 255.
[53] W. F. Mayers, ‘Chinese Notes and Queries,’ Aug. 1868, p. 123.
[54] ‘Proc. Zoolog. Soc.’ May 25, 1842.)
[55] Yarrell’s ‘British Fishes,’ vol. i. p. 319.
[56] ‘Dict. Class. d’Hist. Nat.,’ tom. v. p. 276.
[57] ‘Observations in Nat. Hist.,’ 1846, p. 211. Dr. Gray has described, in ‘Annals and Mag. of Nat. Hist.,’ 1860, p. 151 a nearly similar variety but destitute of a dorsal fin.
[58] ‘De l’Espèce,’ 1859, p. 459. With respect to the bees of Burgundy see M. Gerard, art. ‘Espèce,’ in ‘Dict. Univers. d’Hist. Nat.’
[59] See a discussion on this subject, in answer to a question of mine, in ‘Journal of Horticulture,’ 1862, pp. 225-242; also Mr. Bevan Fox, in ditto, 1862, p. 284.
[60] This excellent observer may be implicitly trusted; see ‘Journal of Horticulture,’ July 14th, 1863, p. 39.
[61] ‘Journal of Horticulture,’ Sept. 9th, 1862, p. 463; see also Herr Kleine on same subject (Nov. 11th, p. 643, who sums up, that, though there is some variability in colour, no constant or perceptible differences can be detected in the bees of Germany.
[62] Mr. Woodbury has published several such accounts in ‘Journal of Horticulture,’ 1861 and 1862.
[63] ‘Annals and Mag. of Nat. Hist.,’ 3rd series, vol. xi. p. 339.
[64] ‘The Cottage Gardener,’ May 1860, p. 110; and ditto in ‘Journal of Hort.,’ 1862, p. 242.
[65] ‘Transact. Entomolog. Soc.’ 3rd series, vol. iii. pp. 143-173 and pp. 295-331.
[66] Godron, ‘De l’Espèce,’ 1859, tom. i. p. 460. The antiquity of the silkworm in China is given on the authority of Stanislas Julien.
[67] See the remarks of Prof. Westwood, Gen. Hearsey and others at the meeting of the Entomolog. Soc. of London, July, 1861.
[68] See for instance M. A. de Quatrefages’ ‘Études sur les Maladies actuelles du Ver à Soie,’ 1859, p. 101.
[69] My authorities for the statements will be given in the chapter on Selection.
[70] ‘Manuel de l’Éducateur de Vers à Soie,’ 1848.
[71] Robinet, ibid., pp. 12, 318. I may add that the eggs of N. American silkworms taken to the Sandwich Islands produced moths at very irregular periods; and the moths thus raised yielded eggs which were even worse in this respect. Some were hatched in ten days, and others not until after the lapse of many months. No doubt a regular early character would ultimately have been acquired. See review in ‘Athenæum,’ 1844, p. 329, of J. Jarves’ ‘Scenes in the Sandwich Islands.’
[72] ‘The Art of rearing Silk-worms,’ translated from Count Dandolo, 1825, p. 23.
[73] ‘Transact. Ent. Soc.,’ ut supra, pp. 153, 308.
[74] Robinet, ibid., p. 317.
[75] Robinet, ibid., pp. 306-317.
[76] ‘Transact. Ent. Soc.,’ ut supra, p. 317.
[77] Stephen’s Illustrations, ‘Haustellata,’ vol. ii. p. 35. See also Capt. Hutton, ‘Transact. Ent. Soc.,’ ibid., p. 152.
[78] ‘Études sur les Maladies du Ver à Soie,’ 1859, pp. 304, 209.
[79] Quatrefages, ‘Études,’ etc., p. 214.
[80] ‘Transact. Ent. Soc.,’ ut supra, p. 151.
[81] ‘Manuel de l’Educateur,’ etc., p. 26.
[82] Godron, ‘De l’Espèce,’ p. 462.
[83] Quatrefages, ‘Études,’ etc., pp. 12, 209, 214.
[84] Robinet, ‘Manuel,’ etc., p. 303.
[85] Robinet, ibid., p. 15.