THE CAUSE OF MIMETIC RESEMBLAJfCE ETC. OOU 



of the principal records of such observations are to be found in 

 tlie ' Transactions ' of this Society. 



"W. S. MacLeay, in his ' Horae Entomologic<B ' (London, 1819 

 and 1821), alluded to certain cases which are now included under 

 Mimicry, viz. the likeness of some Diptera to Hymenoptera 

 (Pt. II. p. 365), and interpreted them, together with many other 

 resemblances of structure and life-history, by the principle of 

 Analogy as distinct from Affinity in Nature. These views were 

 adopted by MacLeay's immediate successors. 



The Eev. "William Kirby read " A Description of some Insects 

 which appear to exemplify Mr. William S. MacLeay's Doctrine 

 of Affinity and Analogy," before this Society on Dec. 17th, 1822, 

 and the paper was published in the ' Transactions ' (vol. xiv. 

 p. 93). 



Boisduval, in the ' Species Greueral des Lepidopteres,' pub- 

 lished in 18,30, remarked (pp. 372, 373) on the resemblance 

 between certain West African butterflies belonging to very 

 different sroups. 



Prof. Westwood read " Illustrations of the Eelationships ex- 

 isting among Natural Objects, usually termed Affinity and 

 Analogy, selected from the Class of Insects," before this Society, 

 on Jan. 17th and May 2nd, 1837, the paper appearing in the 

 'Transactions' (vol. xviii. p. 409). In the paper many new 

 examples were published and figured, while MacLeay's views 

 were criticised aud expanded in an interesting manner. 



The same recognition of Mimicry is equally well seen in the 

 names wdth the ternunation -formis given to so many of our 

 moths, indicating their resemblance to wasps, bees, and other 

 insects. In spite, however, of the knowledge of a large number 

 of instances, the subject made no real progress until the appear- 

 ance of H. W. Bates's paper. The view then set forth that the 

 resemblances are in themselves beneficial to the possessor was, as 

 far as I am aware, only once suggested before, — in the w^ell-known 

 ' Introduction ' by Kirby and Spence. In Vol. II. p. 223 of the 

 second edition (1817) the authors write as follows : — " Some 

 singular larvae with a radiated anus live in the nests of humble- 

 bees, and are the offspring of a particular genus of flies {Volu- 

 cella, Geoffr., Pterocera, Meigeu), many of the species of which 

 strikingly resemble those bees in shape, clothing, and colour. 

 Thus has the Author of nature provided that they may enter 

 those nests aud deposit their eggs undiscovered. Did these 



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