This suggests that the perfect imitation in shape, as well as in movement, seen in many species was started in forms of an appropriate size and colour by the mimicry of movement alone." Up to the present time Burchell is the only naturalist who has observed an example which still exhibits this ancestral stage in the evolution of mimetic likeness.
Following the teachings of his day, Burchell was driven to believe that it was part of the fixed and inexorable scheme of things that these strange superficial resemblances existed. Thus, when he found other examples of Hemipterous mimics, including one (Luteva macrophthalma) with "exactly the manners of a Mantis," he added the sentence, "In the genus Cimex (Linn.)are to be found the outward resemblances of insects of many other genera and orders" (February 15, 1829). Of another Brazilian bug, which is not to be found in his collection, and cannot therefore be precisely identified, he wrote: "Cimex...Nature seems to have intended it to imitate a Sphex, both in colour and the rapid palpitating and movement of the antennae"(November 15, 1826). At the same time it is impossible not to feel the conviction that Burchell felt the advantage of a likeness to stinging insects and to aggressive ants, just as he recognised the benefits conferred on desert plants by spines and by concealment. Such an interpretation of mimicry was perfectly consistent with the theological doctrines of his day. (See Kirby and Spence, "An Introduction to Entomology" (1st edition), London, Vol. II. 1817, page 223.)The last note I have selected from Burchell's manuscript refers to one of the chief mimics of the highly protected Lycid beetles. The whole assemblage of African insects with a Lycoid colouring forms a most important combination and one which has an interesting bearing upon the theories of Bates and Fritz Muller. This most wonderful set of mimetic forms, described in 1902 by Guy A.K. Marshall, is composed of flower-haunting beetles belonging to the family Lycidae, and the heterogeneous group of varied insects which mimic their conspicuous and simple scheme of colouring. The Lycid beetles, forming the centre or "models" of the whole company, are orange-brown in front for about two-thirds of the exposed surface, black behind for the remaining third. They are undoubtedly protected by qualities which make them excessively unpalatable to the bulk of insect-eating animals. Some experimental proof of this has been obtained by Mr Guy Marshall. What are the forms which surround them?
According to the hypothesis of Bates they would be, at any rate mainly, palatable hard-pressed insects which only hold their own in the struggle for life by a fraudulent imitation of the trade-mark of the successful and powerful Lycidae. According to Fritz Muller's hypothesis we should expect that the mimickers would be highly protected, successful and abundant species, which (metaphorically speaking) have found it to their advantage to possess an advertisement, a danger-signal, in common with each other, and in common with the beetles in the centre of the group.
How far does the constitution of this wonderful combination--the largest and most complicated as yet known in all the world--convey to us the idea of mimicry working along the lines supposed by Bates or those suggested by Muller? Figures 1 to 52 of Mr Marshall's coloured plate ("Trans. Ent. Soc.
Lond." 1902, plate XVIII. See also page 517, where the group is analysed.)represent a set of forty-two or forty-three species or forms of insects captured in Mashonaland, and all except two in the neighbourhood of Salisbury. The combination includes six species of Lycidae; nine beetles of five groups all specially protected by nauseous qualities, Telephoridae, Melyridae, Phytophaga, Lagriidae, Cantharidae; six Longicorn beetles; one Coprid beetle; eight stinging Hymenoptera; three or four parasitic Hymenoptera (Braconidae, a group much mimicked and shown by some experiments to be distasteful); five bugs (Hemiptera, a largely unpalatable group); three moths (Arctiidae and Zygaenidae, distasteful families); one fly. In fact the whole combination, except perhaps one Phytophagous, one Coprid and the Longicorn beetles, and the fly, fall under the hypothesis of Muller and not under that of Bates. And it is very doubtful whether these exceptions will be sustained: indeed the suspicion of unpalatability already besets the Longicorns and is always on the heels,--I should say the hind tarsi--of a Phytophagous beetle.
This most remarkable group which illustrates so well the problem of mimicry and the alternative hypotheses proposed for its solution, was, as I have said, first described in 1902. Among the most perfect of the mimetic resemblances in it is that between the Longicorn beetle, Amphidesmus analis, and the Lycidae. It was with the utmost astonishment and pleasure that I found this very resemblance had almost certainly been observed by Burchell. A specimen of the Amphidesmus exists in his collection and it bears "651." Turning to the same number in the African Catalogue we find that the beetle is correctly placed among the Longicorns, that it was captured at Uitenhage on Nov. 18, 1813, and that it was found associated with Lycid beetles in flowers ("consocians cum Lycis 78-87 in floribus").
Looking up Nos. 78-87 in the collection and catalogue, three species of Lycidae are found, all captured on Nov. 18, 1813, at Uitenhage. Burchell recognised the wide difference in affinity, shown by the distance between the respective numbers; for his catalogue is arranged to represent relationships. He observed, what students of mimicry are only just beginning to note and record, the coincidence between model and mimic in time and space and in habits. We are justified in concluding that he observed the close superficial likeness although he does not in this case expressly allude to it.
