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The ichneumon fly and the equilibration of British natural economies in the eighteenth century

Published online by Cambridge University Press:  27 October 2015

Kaplan Institute for the Humanities, Northwestern University, 1800 Sherman Ave, Suite 1-200, Evanston, IL, 60208, USA. Email:


The parasitic ichneumon fly, discovered by European natural philosophers in the seventeenth century, remained largely unstudied until it captured the attention of Enlightenment-era natural historians. Although this sudden surge of interest has been explained as an effort to understand the natural ‘evil’ of parasitism, the heyday of ichneumon studies was actually inspired by the political and agricultural context of late eighteenth-century Britain. British naturalists were captivated by this insect for reasons both philosophical and practical. In the providentially self-equilibrating qualities of ‘natural’ ichneumon economies, they saw solutions to political problems of famine, dearth, national wealth, governance and excess population, in addition to finding reassurance that Enlightened confidence in nature's inherent stability and fruitfulness was not unfounded.

Research Article
Copyright © British Society for the History of Science 2015 

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1 Dru Drury and John O. Westwood, Illustrations of Exotic Entomology, Containing Upwards of Six Hundred and Fifty Figures and Descriptions of Foreign Insects, 3 vols., London: H.G. Bohn, 1837, vol. 1, p. 93. The original work was Drury's own, published in three volumes in 1770, 1773 and 1782.

2 For the importance of metaphor in guiding the ecological sciences see Donald Worster, Nature's Economy: A History of Ecological Ideas, 2nd edn, New York: Cambridge University Press, 1985, pp. xiv–xv.

3 Despite the difficulty of using the word ‘entomologist’ to describe natural historians of the eighteenth century, the author occasionally employs the term to denote those naturalists who focused their entire effort on insects, as Drury did.

4 Stephen Jay Gould, Hen's Teeth and Horse's Toes, New York: Norton, 1983, p. 43.

5 Gould, op. cit. (4), pp. 32–45.

6 William Kirby and William Spence, An Introduction to Entomology, or, Elements of the Natural History of Insects, 2nd edn, 4 vols., London: Longman, Hurst, Rees, Orme, and Brown, 1816, vol. 1. The second edition is cited here as it is more readily available than the first. There are no significant differences between these editions.

7 Pauly, Philip J., ‘Fighting the Hessian fly: American and British responses to insect invasion, 1776–1789’, Environmental History (2002) 7, pp. 485507CrossRefGoogle Scholar.

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9 C.A. Bayly, Imperial Meridian: The British Empire and the World 1780–1830, New York: Longman, 1989; Richard Drayton, Nature's Government: Science, Imperial Britain and the ‘Improvement’ of the World, New Haven: Yale University Press, 2000.

10 Margaret Schabas, ‘Adam Smith's debts to nature’, in Margaret Schabas and Neil DiMarchi (eds.), Oeconomies in the Age of Newton, Durham, NC: Duke University Press, 2003, pp. 262–281; Schabas, The Natural Origins of Economics, Chicago: The University of Chicago Press, 2005.

11 Dipteran parasitoids or parasitoid flies appear occasionally in eighteenth-century works alongside their Hymenopteran counterparts. Maria Sybilla Merian's paintings contain many easily identified tachinid flies. Maria Sybilla Merian, De Europische Insecten, Naauwkeurig Onderzogt, Na't Leven Geschildert, En in Print Gebragt Door, Amsterdam: J.F. Bernard, 1773, Plates 33, 73, 93, 124 and 143.

12 Nick Mills, ‘Parasitoids’, in Vincent H. Resh and Ring Cardé (eds.), The Encyclopedia of Insects, San Diego: Academic Press, 2003, pp. 845–846.

13 Merian depicted ectoparasitoid egg sacks on at least one occasion. Merian, op. cit. (11), Plate 93, bottom.

14 Moses Harris, The Aurelian: Or, Natural History of English Insects, London: For the Author, 1766, p. 80; James Rennie, Insect Transformations, London: Longman, Rees, Orme, Brown, and Green, 1830, p. 60. On the intellectual history of surprise or wonder see Lorraine Daston and Katherine Park, Wonders and the Order of Nature, New York: Zone Books, 1998, Chapter 8.

15 Oak galls were associated in Britain with the Restoration in the form of ‘Oak Apple Day’. J.C. Loudon, Arboretum Et Fruticetum Brittannicum; or, the Trees and Shrubs of Britain, 8 vols., London: Longman, Orme, Brown, Green, and Longmans, 1838, vol. 3, pp. 1823–1824.

16 William Derham was likely the last naturalist to class galls with ichneumons, even though he understood the life cycle of the parasitoid and was even able to differentiate between dipterous (‘musca’) and hymenopteran (‘vespa’) parasitoids. William Derham, Physico Theology: Or, a Demonstration of the Being and Attributes of God from His Works of Creation, 13th edn, London: Robinson and Roberts, 1768, p. 241. For parasitoid life cycle, p. 379; for ‘musca’ and ‘vespa’ ichneumons, p. 228.

17 Merian, op. cit. (11), Plate 93. Eleazar Albin, A Natural History of English Insects Illustrated with a Hundred Copper Plates, Curiously Engraven from the Life, London: Printed by William and John Innys, 1724. Dozens of ichneumons occur in the English Insects and are mentioned in the text accompanying each painting, usually at the end of the page.

18 Lister, Martin, ‘Some Additions of Mr. Lyster to His Former Communications about Vegetable Excrescencies and Ichneumon Wasps: Together with an Inquiry Concerning Tarantulas’, Philosophical Transactions of the Royal Society (1671) 6, pp. 30043005Google Scholar.

19 Lister, Martin, ‘A Letter of Mr. Martin Lister, Written at York August 25 1671, Confirming the Observation in No. 74 About Musk Sented Insects; Adding Some Notes Upon D. Swammerdam's Book of Insects, and on That of M. Steno Concerning Petrify'd Shell’, Philosophical Transactions of the Royal Society (1671) 6, pp. 22812284CrossRefGoogle Scholar, 2281. John Ray's correspondence with Lister is warm and entomological; see The Correspondence of John Ray: Consisting of Selections from the Philosophical Letters Published by Dr. Derham and Original Letters of John Ray in the Collection of the British Museum (ed. Edwin Lankester), London: Printed for the Ray Society,1848. Lister to Ray, 8 February 1670.

20 John Ray, The Wisdom of God Manifested in the Works of the Creation, in Two Parts, 6th edn, London: Printed for William Innys, 1714, p. 322.

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22 Tremblay, E. and Masutti, L., ‘History of insect parasitism in Italy’, Biological Control (2005) 32, pp. 3439CrossRefGoogle Scholar; Lenteren and Godfray, op. cit. (21), p. 17. Italian naturalist Ulisse Aldrovandi (1522–1605) recorded a parasitoid hatching in a woodcut print in 1602, calling it an ‘alternate form of the usual butterfly’. R.G. Van Driesche and M.S. Hoddle, ‘Biological control of insect pests’, in Vincent H. Resh and Ring Cardé (eds.), Encyclopedia of Insects, New York: Academic Press, 2003, pp. 103–115.

23 Pliny, The Natural History of Pliny, 6 vols., London: G. Bell & Sons, 1890, vol. 2, pp. 286–287, Book 8:35–36.

24 Aiken, Pauline, ‘The animal history of Albertus Magnus and Thomas of Cantimpré’, Speculum (1947) 22, pp. 205225CrossRefGoogle Scholar, 211. William Wood, Zoography: Or, the Beauties of Nature Displayed in Select Description from the Animal, and Vegetable, 3 vols., London: Cadell and Davies, In the Strand, 1807, vol. 1, pp. 256–259; ‘The Ichneumon’, Saturday Magazine (1841) 559, pp. 109–110; Foucher d'Obsonville, Philosophic Essays on the Manners of Various Foreign Animals, with Observations on the Law and Customs of Several Eastern Nations (tr. Thomas Holcroft), London: John Johnson, 1784, pp. 75–79.

25 An Account of the Ichneumon’, The Bee: Or Literary Weekly Intelligencer (1792) 12(102), pp. 8184Google Scholar.

26 Moffett used the word ‘Phalangia’ to describe these spiders, a general term that meant only ‘any venomous spider’ in the seventeenth century and did not indicate the harmless spiders that inhabit the Phalangium genus today. Edward Topsell et al., The History of Four-Footed Beasts and Serpents, 2 vols., London: G. Sawbridge, 1658, vol. 2, pp. 1061–1062. For the harmlessness of modern Phalangium, Oxford English Dictionary Online, ‘Phalangium’, at, accessed 5 November 2012. For Aristotle's ichneumon see Aristotle, History of Animals in Ten Books (tr. Richard Cresswell), London: George Bell and Sons, 1883, p. 127, Book 5:15.

27 Edward Newman, ‘Further Observations on the Septenary System’, Entomological Magazine (1837) 4, pp. 234–251, 247.

28 A.H. Haliday, ‘An Essay on the Classification of the Parasitic Hymenoptera, Which Correspond with the Ichneumones Minuti of Linnaeus’, Entomological Magazine (1833) 1(3), pp. 259–276; William Kirby, Monographia Apum Angliæ, Ipswich: Printed for the Author by J. Raw, 1802; A.H. Haliday, ‘Essay on Parasitic Hymenoptera’, Entomological Magazine (1834) 4(2), pp. 92–106; Haliday, ‘Essay on the Classification of Parasitic Hymenoptera’, Entomological Magazine (1834) 2(3), pp. 225–259.

29 Edward Donovan, The Natural History of British Insects, 10 vols., London: Bye and Law, St John's Square, 1802, vol. 2, pp. 12–14; vol. 3, pp. 56–57; vol. 10, p. 13. The third volume of Donovan's work also finds room for the Sphex sabulosa, which had only recently been removed from the ichneumon category. Another insect that he is careful to parse from the ichneumon is the Sirex spectrum, which resembles it; ibid., vol. 7, p. 25. For the ichneumon's host insects see ibid., vol. 4, p. 40.

30 Kirby, op. cit. (28), pp. 3–4.

31 Kathirithamby, Jeyaraney et al. ., ‘Strepsiptera parasites: novel biocontrol tools for oil palm integrated pest management in Papua New Guinea’, International Journal of Pest Management (1998) 44(3), pp. 127133CrossRefGoogle Scholar; Orth, R.E. et al. ., ‘A rove beetle, Ocypus Olens, with potential for biological control of the brown garden snail’, Canadian Entomologist (1975) 107(10), pp. 11111116CrossRefGoogle Scholar; Honěk, Alois et al. , ‘Rove beetles (Coleoptera: Staphylinidae) in an apple orchard’, Plant Protection Science (2012) 48(3), pp. 116221CrossRefGoogle Scholar.

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33 Indeed, historians of taxonomy seem to be focused on questions of artificial versus natural systems based on body parts and definitions of ‘essentialism’ and ‘species fixity’, as well as other topics that dwell in locations even more distant from our question of behaviour. See John S. Wilkins, Species: A History of the Idea, London: University of California Press, 2009; Varma, Charissa S., ‘Threads that guide or ties that bind: William Kirby and the essentialism story’, Journal of the History of Biology (2009) 42, pp. 119149CrossRefGoogle ScholarPubMed; Winsor, Mary P., ‘The development of Linnaean insect classification’, Taxon (1976) 25(1), pp. 5767CrossRefGoogle Scholar.

34 Kirby, op. cit. (28), p. 44.

35 Winsor, op. cit. (33), 59.

36 Carolus Linnaeus and Henricus Christianus Daniel Wilcke, ‘On the Police of Nature’, in Benjamin Stillingfleet (ed.), Select Dissertations from the Amoenitates Academicae: A Supplement to Mr. Stillingfleet's Tracts Relating to Natural History, London: G. Robinson and J. Robson, 1781, pp. 129–166, 143. Linnaeus was likely the author of most of the dissertations in the Stillingfleet tracts.

37 For overpopulation parables in natural history see Fredrik Albritton Jonsson, Enlightenment's Frontier: The Scottish Highlands and the Origins of Environmentalism, New Haven: Yale University Press, 2013, pp. 188–212. For Linnaeus on the economy of nature see Egerton, Frank N., ‘A history of the ecological sciences part 23: Linnaeus and the economy of nature’, Bulletin of the Ecological Society of America (2007) 88, pp. 7288CrossRefGoogle Scholar.

38 Raeff, Marc, ‘The well-ordered police state and the development of modernity in seventeenth- and eighteenth-century Europe: an attempt at a comparative approach’, American Historical Review (1975) 80, pp. 12211234CrossRefGoogle Scholar. Jonsson, op. cit. (37), distinguishes the British ‘police’ state as one which located such policing within civil society.

39 Winsor, op. cit. (33), p. 59.

40 Raeff, op. cit. (38), p. 1226.

41 Rollin, Bernard E., ‘Animal mind: science, philosophy, and ethics’, Journal of Ethics (2007) 11, pp. 253274CrossRefGoogle Scholar, 254–255.

42 Kirby and Spence, op. cit. (6), vol. 2, p. 225.

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44 Guerrini, Anita, ‘The ethics of animal experimentation in seventeenth-century England’, Journal of the History of Ideas (1989) 50, pp. 391407CrossRefGoogle ScholarPubMed.

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46 ‘An Account of the Ichneumon’, op. cit. (25), pp. 81–82.

47 Oliver Goldsmith, An History of the Earth and Animated Nature, in Eight Volumes, Dublin: James Williams, 1777, vol. 1, for incorrigible nature p. 221, for courage p. 130.

48 ‘Entomology’, in Thomas Curtis (ed.), The London Encyclopaedia: Or, Universal Dictionary of Science, Art, Literature, and Practical Mechanics, London: For Thomas Tegg, 1829, pp. 477–478.

49 Donovan, op. cit. (29), vol. 2, p. 14.

50 Rennie, op. cit. (14), p. 61.

51 Explanation of the Phenomenon Respecting the Caterpillar’, The Bee: or Literary Weekly Intelligencer (1792) 11, p. 287Google Scholar.

52 Donovan, op. cit. (29), vol. 2, p. 14.

53 Drury and Westwood, op. cit. (1), pp. 93–94.

54 On Earth as a ‘habitable’ planet see Clarence Glacken, Traces on the Rhodian Shore: Nature and Culture in Western Thought from Ancient Times to the End of the Eighteenth Century, Berkeley: University of California Press, 1967, pp. 375–429.

55 Oliver Goldsmith, The History of the Earth and Animated Nature, 8 vols., London: Printed for J. Nourse, in the Strand, 1774, vol. 8, p. 114.

56 ‘Entomology’, op. cit. (48), p. 477. The entry for 1829 is the same as the one published in 1839. Later, more specialized encyclopedias would continue to quote Kirby's declaration on the insect. ‘Ichneumon’, in Charles Knight (ed.), Natural History, Or, The Second Division of ‘The English Cyclopaedia’, London: Bradbury, Evans, and Co., 1867, pp. 197–198. Interestingly, these encyclopedia entries omit the section about ‘God's mercy’, but still imply a final cause or purpose to the activity of the ichneumon through the use of the phrase ‘proper limits’.

57 Drury and Westwood, op. cit. (1), pp. 93–94.

58 Edward Newman, The Grammar of Entomology, London: Frederick Westley and A.H. Davis, 1835, pp. 40–41.

59 Clark, J.F.M., ‘History from the ground up: bugs, political economy, and God in Kirby and Spence's Introduction to Entomology (1815–1856)’, Isis (2006) 97, pp. 2855CrossRefGoogle ScholarPubMed, 29. Clark's excellent article describes the relationship between the political economist and theologian and the way their respective societal roles were reflected in the Introduction.

60 Kirby and Spence, op. cit. (6), vol. 1.

61 Kirby and Spence, op. cit. (6), vol. 1, p. 248. Kirby, unlike his seventeenth-century predecessors, believed there was little restriction on human efforts to reduce insect populations, although the outcome of such effort was determined entirely by God.

62 Kirby and Spence, op. cit. (6), pp. 240–241.

63 Erasmus Darwin, The Temple of Nature, or, the Origin of Society, a Poem, Baltimore: John Butler and Bonsal and Niles, 1804, p. 156, lines 34–38.

64 Darwin, op. cit. (63), p. 167, lines 135–44.

65 Kirby and Spence, op. cit. (6), vol. 1, pp. 31, 38, 265, 302, 306, 425.

66 Darwin, op. cit. (63), p. 188, lines 369–380.

67 Kirby and Spence, op. cit. (6), p. 120.

68 Kirby and Spence, op. cit. (6), pp. 260–279 for the Introduction's lengthiest treatment of policing tactics of the predator bugs and ichneumon, p. 269 for the ‘horrors of famine’.

69 ‘Ichneumon’, The Supplement to the Penny Cyclopædia of the Society for the Diffusion of Useful Knowledge, London: Charles Knight, 1846, p. 70; Edwin Sidney, The Blights of Wheat and Their Remedies, London: Religious Tract Society, 1846, p. 130. By 1867, the moral weight of the ‘horrors of famine’ was sometimes actively repudiated in entries on the ichneumon, as in a posthumously published essay, Newman, Edward, ‘Collected Observations on the British Sawflies by the Late Edward Newman’, The Entomologist (1878) 11(182), pp. 147154Google Scholar, p. 150.

70 M.E. Turner, J.V. Beckett and B. Afton, Farm Production in England, 1700–1914, New York: Oxford University Press, 2001, p. 210; V.G. Dethier, Man's Plague? Insects and Agriculture, Princeton: Darwin Press, 1976, p. 54. For the insect paradox see James E. McWilliams, American Pests: The Losing War on Insects from Colonial Times to DDT, New York: Columbia University Press, 2008, p. 24–25. For the axiomatic nature of the idea that pest increase accompanies agriculture see May R. Berenbaum, Bugs in the System: Insects and Their Impact on Human Affairs, New York: Helix Books, 1995, pp. 106–107. For the other factors in pest increase, such as weaker plants generated by excessive weeding and breeding, see Dethier, op. cit., p. 54. Dethier's best example of cross-pollination with wild grain comes from South America, with maize and teosinte, but similar episodes were occurring in Europe with wheat, oats and rye.

71 Turner, Beckett and Afton, op. cit. (70), pp. 212–213.

72 Kirby, ‘Tipula Tritici’, op. cit. (32); Kirby, ‘Strepsiptera’ op. cit. (32); Kirby, ‘Addendum’, op. cit. (32); Kirby, ‘Three Notebooks’, op. cit. (32); Marsham, Thomas, ‘Further Observations on the Wheat Insect in a Letter to the Reverend Samuel Goodenough’, Transactions of the Linnean Society (1798) 4, pp. 224229CrossRefGoogle Scholar. In these works, Kirby appears to be involved with at least three different kinds of ichneumon, including the Strepsiptera.

73 Kirby, ‘Tipula Tritici’, op. cit. (32), p. 235. Kirby was citing Job 13:11 here, as well as Linnaeus's Systema Natura: ‘Finis creationis telluris est gloria Dei ex opere naturae per hominem solum’, meaning, ‘There is no clearer expression of his admiration than his placing man above the rest of creation’.

74 The ESL later transformed into the modern Royal Entomological Society.

75 Westwood spoke at an anniversary meeting of the ESL on 26 January 1835, in an ‘Address on the Recent Progress and Present State of Entomology’. Audrey Z. Smith, A History of the Hope Entomological Collections in the University Museum Oxford, with Lists of the Archives and Collections, Oxford: Clarendon Press, 1986, p. 38.

76 Pauly, op. cit. (7).

77 For the equilibration argument in 1782 see William Curtis, A Short History of the Brown-Tail Moth and the Caterpillars of Which Are at Present Uncommonly Numerous and Destructive in the Vicinity of the Metropolis, London: B. White, J. Sewell, J. Johnson, J. Strahan, R. Faulder, 1782.

78 ‘Rosa Muscosa’, in Philip Miller (ed.), The Gardeners Dictionary; Containing the Best and Newest Methods of Cultivating and Improving the Kitchen, Fruit, Flower Garden, and Nursery, London: For the Author, 1768, n.p; ‘Bedegua’, in John Mason Good, Olinthus Gregory and Newton Bosworth (eds.), Pantologia: A New Cyclopaedia, Comprehending a Complete Series of Essays, Treatises and Systems, London: T. Davison, 1813, n.p.

79 Thomas Potts, ‘Bush Vetch’, in Potts (ed.), The British Farmers Cyclopedia: Or, Complete Agricultural Dictionary of Improved Modern Husbandry, London: B. Crosby, 1808, n.p; James Adams, Practical Essays on Agriculture, Containing an Account of Soils and the Manner of Correcting Them, 2 vols., London: T. Cadell, 1789, vol. 1, p. 459. Adams echoes Swayne and pairs the ichneumon with an aggressive pest, the weevil.

80 George Swayne, ‘On the Culture of the Bush Vetch, a Letter to the Secretary of the Society for the Encouragement of Agriculture, Arts, Manufactures and Commerce at Bath. Oct. 13 1785’, in Letters and Papers on Agriculture, Planting &C, Addressed to the Society Instituted at Bath for the Encouragement of Agriculture, Arts, Manufactures and Commerce, London: R. Crutwell, 1786, pp. 71–78.

81 Louis Narcisse Baudry des Lozières, Voyage a La Louisiane: Et Sur Le Continent De L'amérique Septentrionale, Fait Dans Les Années 1794 À 1798, Paris: Dentu, 1802; Second Voyage a La Louisiane’, Edinburgh Review; A Critical Journal (1803) 3(5), pp. 8190Google Scholar, 89.

82 ‘Thomas Ruggles, 1745–1818’, in Harry Inglis (ed.), Dictionary of Political Economy, Chicago: McMillan, 1913, p. 332.

83 Thomas Ruggles, ‘Wheat Insect, Nov 16, 1800’, in Arthur Young (ed.), Annals of Agriculture and Other Useful Arts, Collected and Published by Authur Young, Secretary to the Board of Agriculture, Bury St Edmund's: Rackham, 1801, pp. 133–142, 140.

84 Thomas Ruggles, ‘Wheat Insect, Dec 9, 1800’, in Young, op. cit. (83), pp. 215–217.

85 The wireworm, apple aphis, turnip fly, hops fly and wheat midge (and possibly the cane fly and cassava/indigo worm) were the main pest problems in Britain and the empire in this period.

86 Thomas Marsham, ‘On the Wire Worm’, in Communications to the Board of Agriculture on Subjects Relative to the Husbandry and Internal Improvement of the Country, London: W. Bulmee, 1805, pp. 412–415, Clas Bierkander's entire article on the ‘Root Worm’ is included in Marsham's letter, pp. 413–415.

87 Marsham, op. cit. (86), p. 415.

88 Marsham, op. cit. (86), p. 412.

89 John Sinclair, An Account of the Systems of Husbandry Adopted in the More Improved Districts of Scotland; with Some Observations on the Improvements of Which they are Susceptible, 2nd edn, 2 vols., Edinburgh, 1813, vol. 2, Appendix 35, p. 134.

90 John Sinclair, General Report of the Agricultural State and Political Circumstances of Scotland, Drawn up for the Consideration of the Board of Agriculture and Internal Improvement under the Directions of the Right Honorable John Sinclair (President), 3 vols., Edinburgh: Abernethy and Walker, 1814, vol. 3, p. 405.

91 Sinclair, op. cit. (90), 401.

92 Hörstadius, Sven, ‘Linnaeus, animals, and man’, Biological Journal of the Linnaean Society (1974) 6(4), pp. 269275CrossRefGoogle Scholar, 272. Hörstadius, a renowned experimental embryologist writing from Sweden in 1974, seems to be the original source for this quote, which he does not cite. Jacobson, C.O., ‘Sven Otto Hörstadius. 18 February 1898–16 June 1996’, Biographical Memoirs of Fellows of the Royal Society (2000) 46, pp. 245256Google Scholar.

93 Erasmus Darwin, Phytologia: Or, the Philosophy of Agriculture and Gardening, London: J. Johnson, 1800, p. 360.

94 Darwin, op. cit. (93), p. 356.

95 Darwin, op. cit. (63), pp. 48, 54.

96 Henslow, J.S., ‘Report on Diseases of the Wheat’, Journal of the Royal Agricultural Society of England (1840) 2, pp. 125Google Scholar, 24–25.

97 Henslow, J.S., ‘Observations on the Wheat-Midge’, Journal of the Royal Agricultural Society of England (1841) 2, pp. 3640Google Scholar, 36.

98 John Curtis, Farm Insects: Being the Natural History and Economy of the Insects Injurious to the Field Crops of Great Britain and Ireland, and Also Those Which Infest Barns and Granaries, Edinburgh: Blackie and Son, 1860, p. 98.

99 P. DeBach and D. Rosen, Biological Control by Natural Enemies, Cambridge: Cambridge University Press, 1991. Chapters 4 and 5 outline historical biocontrol measures by insects. See also Charles V. Riley, Parasitic and Predaceous Insects in Applied Entomology, Washington, DC: Government Printing Office, 1893, pp. 133–134.

100 Curtis, John, ‘Observations on the Natural History and Economy of Various Insects Affecting the Turnip Crops, Including the White Cabbage Butterflies, the Turnip Seed Weevil, &C’, Journal of the Royal Agricultural Society of England (1842) 3, pp. 306323Google Scholar, 310.

101 Curtis, op. cit. (98), p. 279. Curtis was still citing Kirby in 1860, not to praise the just equilibrium, but to revisit the long-standing confusion of the ichneumon and Tipula by laymen.