Some of the imitations by insects of in- their prey; many spiders are thus endowed; but some hunting spiders mimic flowerbuds, and station themselves motionless in the axils of leaves and other parts of plants. to wait for their victims. animate and living objects are very singular, and may be mentioned in this place. Many caterpillars of moths, but sometimes the cases only which are manufactured and inhabited by the caterpillars, have a most The most extraordinary instance of imitadeceptive likeness to dry twigs and other tion I ever met with was that of a very objects. Moths themselves very frequently large caterpillar, which stretched itself from resemble the bark on which they are found, amidst the foliage of a tree which I was one or have wings colored and veined like the day examining, and startled me by its refallen leaves on which they lie motionless. semblance to a small snake. The first three The accidental general resemblance between segments behind the head were dilatable at the shape of moths' wings and leaves here the will of the insect, and had on each side gives Nature the groundwork for much a large black pupillated spot, which resemmimetic analogy. It has been pointed out bled the eye of the reptile; it was a poisonby Rössler that the buff-tip moth, when at ous or viperine species mimicked, and not rest, is intended to represent a broken piece an innocuous or colubrine snake; this was of lichen-covered branch-the colored tips proved by the imitation of keeled scales on of these wings, when they are closed, resem- the crown, which was produced by the rebling a section of the wood. Other moths cumbent feet, as the caterpillar threw itself are deceptively like the excrement of birds backwards. The Rev. Joseph Greene, to on leaves. I met with a species of phytopha- whom I gave a description, supposes the gous beetle (chlamys pilula) on the Ama-insect to have belonged to the family Notozons, which was indistinguishable by the eye from the dung of caterpillars on foliage. These two latter cases of imitation should be carefully considered by those who would be inclined to think that the object of mimetic analogies in nature was simply variety, beauty, or ornament; nevertheless these are certainly attendants on the phenomena; some South American Cassida resemble glittering drops of dew on the tips of leaves, owing to their burnished pearly gold color. Some species of Longicorn Coleoptera have precisely the color and sculpture of the bark of the particular species of tree on which each is found. It is remarkable that other species of the same small group of Longicornes (phacellocera buquettii, cyclopeplus batesii) counterfeit, not inanimate objects, like their near kindred just cited, but other insects, in the same way as the Leptalides do the Heliconidæ. dontidae, many of which have the habit of thus bending themselves. I carried off the caterpillar and alarmed every one in the village where I was then living to whom I showed it. It unfortunately died before reaching the adult state. A similar series of mimetic analogies occurs in the Old World, between the Asiatic and African Danaidæ, or representatives of the Heliconida, and species of other families of butterflies and moths. No instance is known in these families of a tropical species of one hemisphere counterfeiting a form belonging to the other. A most remarkable case of mimicry has been recorded by Mr. Trimen in a Papilio of South Africa (P. Cenea), whose male wears to deception the livery of one species of Danais, whilst the female resembles a quite different one. Mimetic analogies, however, are not confined to the Lepidoptera; most orders of insects supply them; but they are displayed only by certain families. Many instances are known where parasitic bees and twowinged flies mimic in dress various industrious or nest-building bees, at whose expense they live, in the manner of the cuckoo. I found on the banks of the Amazons many of these cuckoo bees and flies, which all wore the livery of working bees. peculiar to the country. Amongst the living objects mimicked by insects are the predacious species from which it is the interest of the mimickers to be concealed. Thus, the species of Scaphura (a genus of crickets) in South America resemble in a wonderful manner different sand wasps of large size, which are constantly on the search for crickets to provision their nests with. Another pretty cricket, which I observed, was a good imitation of a tiger beetle, and was always After quoting many other instances found on trees frequented by the beetles (odontocheila). There are endless instances of such mimetic resemblances, Bates of predacious insects being disguised by proceeds to set forth his own explanahaving similar shapes and colors to those of tion of the facts. And here, what he did, as Darwin justly said, was to give | the forest which they inhabit, "it is prob"the requisite touch of genius, and hit able that they are unpalatable to insect on the final cause of all this mimicry." 66 The explanation [says Bates] seems to be quite clear on the theory of natural selection, as recently expounded by Mr. Darwin in the Origin of Species." The local varieties or races cannot be supposed to have been formed by the direct action of physical conditions on the individuals because in limited districts, where these conditions are the same, the most widely 'contrasted varieties are found existing together, and it is inexplicable how they could have produced the nice adaptations which these diverse varieties exhibit. Neither can these adapted races, as before remarked, have originated in one generation by sports, or a single act of variation in each case. It is clear, therefore, that some other active principle must be here at work to draw out, as it were, steadily in certain directions, the suitable variations which arise, generation after generation, until forms have resulted which, like our races of Leptalis Theonoë, are considerably different from their parent as well as their sister forms. enemies. Some of them have exsertile glands near the arms, which are protruded when the insects are roughly handled; it is well known that similar organs in other families secrete fetid liquids or gases, and serve as a protection to the species. I never saw the flocks of slow-flying Heliconidæ in the woods persecuted by birds or dragonflies, to which they would have been an easy prey; nor, when at rest on leaves, did they appear to be molested by lizards or the predacious flies of the family Asilide, which were very often seen pouncing on butterflies of other families. If they owe their flourishing existence to this cause, it would be intelligible why the Leptalidæ, whose scanty number of individuals reveals a less protected condition, .should be disguised in their dress, and thus share their immunity." This theory of mimicry forms Bates's principal contribution to the philosophy of evolution. It was eagerly accepted by Darwin, as were also his views on the nou-extension of the glacial epoch to the equatorial regions. The correspondence on these and kindred subjects between Darwin, Sir Joseph Hooker, and Bates, published in the memoir by Mr. Clodd, is full of illus This principle can be no other than natural selection, the selecting agents being insectivorous animals, which gradually destroy those sports or varieties that are not sufficiently like Ithomic to deceive them.trative scientific interest; but "for the . . Such, I conceive, is the only way in which the origin of mimetic species can be explained. I believe the case offers a most beautiful proof of the truth of the theory of natural selection. It also shows that a new adaptation, or the formation of a new species, is not effected by great and sudden change, but by numerous small steps of natural variation and selection. benefit of the ladies and the country members" (as our ancestors used to say in the happy days before Girton and University Extension), I prefer to quote a few notes from the journal of this period, which show Bates rather in the more popular character of a keen observer of men and manners. Here is a charming word-picture of Sir Charles To quote Mr. Clodd's admirable sum- Lyell : ming up of the argument: 1. Two questions suggest themselves. Why are the Heliconidæ, which by their brilliant coloring attract the eye of insectivorous birds, and by their slowness on the wing are easily seized, mimicked more than other families of butterflies? and, 2. Why are insects so much more subjects of mimicry than other animals? Both questions are answered by Bates. As there is nothing apparent in the structure or habits of the Heliconide which could render them safe from persecution by the numerous insectivorous animals which are ever on the watch in the same parts of Sunday, November 29th, 1863. This afternoon, when walking in the Zoological Gardens with little Alice and the maid, Sir Charles Lyell accosted me near the seal pond, and we walked about together for an hour or so. He was wriggling about in his usual way, with spy-glass raised by fits and 66 Mr. Walstarts to the eye, and began: -ahlace, I believe My name's Bates." "Oh, I beg pardon, I always confound you two." (His memory must be very bad, for we have often met, and I was once his guest at the Geological Club dinแ "Ah ner, Clunn's Hotel, Covent Garden.) - did you see the new porpoise the other day?" "No; I did not happen to be in | is very full of it. What a striking account. the gardens, and it lived but a very short 66 66 you give of the landslips. It is very interesting to us geologists, and"-turning round and speaking very confidentially"your description is remarkably well done." Sir Charles Lyell has the appearance of a. fidgety man not well at ease with himself. We then began talking about my book of He is very greedy of fame, and proud of his travels, and I told him I had just received aristocratic friends and acquaintances. He a request from Mr. Murray to prepare a does not seem to be a very ready man; his second abridged and popular edition. It learning does not appear to be at his fingers' was a capital opportunity to get good advice ends; so that when a subject is suddenly about second editions and abridgements, so presented to him he has difficulty in collectI asked Sir Charles what he would recom- ing his scattered thoughts and bringing mend me to do. forth what he knows upon it. But then he is getting an old man now. Mr. Davidson told me that he was a very hesitating writer, and re-wrote every sentence three or four times on the average, as Mr. Davidson confessed to me was his own case. But, like a well-bred gentleman, Sir Charles can become very sociable, and evidently likes a good dinner with brilliant conversation; Darwin says he likes to hear himself talk. At the Geological Club dinner when I sat at his left fronting Sir Roderick Murchison and Bishop Colenso, he made me laugh by retailing a very good thing. The conversation ran on the comparative merits of the scientific hypothesis of the origin of man and the Biblical one: "Why," says he, "the question resolves itself into few words: Is man modified mud or modified monkey?" But he gave it not as his own. Well now, in the first place," he said, you had better follow the counsels of Murray. Publishers, you know, are always better judges on these matters than authors. I'll tell you what once happened to me, through acting contrary to publisher's advice. The transaction was with old Murray, not the present one. It was when we were bringing out the first edition of my 'Principles.' We had come to the third volume, and Murray said, 'Now we shall print several hundred copies less of this than of the preceding volumes.' I was very much surprised at this. Why! how! deprive purchasers from the commencement of the chance of completing their copies? No, I can't consent to that.' Nevertheless, Murray was firm; to do otherwise, he said, would entail certain loss. Well, I agreed to take the risk on my own shoulders, and the consequence was I burnt my fingers severely. Precisely the number of copies which Murray had recommended me to print was sold. The rest were left on the shelves, curtailing severely my gains on the whole work. But when a second edition came out, including all three volumes, it sold by thousands. I was a youngster then, and the loss of money was of more consequence to me than it would be now." This is an interesting study of differences in men, for Bates was really much the bigger of the two. But Lyell was a man of science who came at the right then needed; besides which he had moment, and did a piece of work just wealth, position, connections; while Bates was a nobody, and had only genius. As a consequence, Lyell's He asked me how many copies I had fame is as much above his true intelprinted of the first edition. I told him lectual place as Bates's is below it. 1,250. This question seemed to be put for Bates's later days were spent as secthe purpose of secretly comparing my lit-retary to the Geographical Society, and erary success with his own. And the result few indeed were the younger travellers seemed to be satisfactory, for he became who did not owe a debt of gratitude to more frank than ever, and began to praise the explorer of the Amazons. Always my book: unobtrusive, he was content with hav "I find it exceedingly interesting, and I hope you will not abridge any of the naturaling done good work in life, and rarely history parts, which, to me, seem the most expected either praise or recognition. important. Do you know Sir Charles Bun- His greatest biological study is buried in bury?" I told him I had been introduced the pages of a learned society's Transto him, but I forgot when and where. actions;" his life itself was buried in "Well, he likes your book amazingly, and the dull work of his office. Yet he lived till the last keen, active, eager, Many men who thought as freely and taking a vivid interest in the new prob- boldly on religious subjects as Bates lems raised by Romanes and Weis- would have been tempted to treat such mann, against the latter of whom he obtrusive sectarianism with an underwas well-nigh minded to deliver his tone of polite but evident chilliness. soul in a formal answer. His conversa-No man has a right, indeed, thus to tion was charming. As Mr. Clodd well thrust upon others his own private conputs it, there was in him "no trace of victions about matters of the inmost mental ossification." He retained to personal interest. It is an impertinence the end his plasticity and receptivity. of the emotions which many of us His sentences were perfect, clear-cut, would feel inclined to resist with courpure English, so that, taken down teous dissent. Bates, however, kept a (alas, that they were not taken down!), draft of his reply, and here it is : not a word need have been altered or MY DEAR SIR, transposed. Of his tolerant gentleness I don't think anything could give those who knew him a better idea than the little episode of his correspondence with Mr. P. H. Gosse, who, besides being a distinguished naturalist, was also a member of the exclusive and peculiarly bigoted sect of Plymouth Brethren. Gosse wrote to Bates on one occasion to send the great naturalist a copy of his 66 Actinologia," and improved the portunity in a somewhat characteristic fashion as follows: op SANDHURST, TORQUAY, February 13th, 1860. MY DEAR SIR, 66 Will you allow me the pleasure of asking your kind acceptance of the accompanying copy of my Actinologia"? I have read your numerous letters from Brazil published in the Zoologist with great interest, partly, doubtless, because I know a little of tropical collecting; and I have mentally followed you to and fro in the scenes and among the lovely insects, which you have so graphically described, with ever increasing sympathy. From one or two expressions dropped here and there in your letters, I have formed a suspicion, moreover, that you are one of those who love the Lord Jesus, and, if so, this would be an additional and far stronger bond of sympathy between us. For there is no union so strong as that between the "holy brotherhood, partakers of the heavenly calling," who by grace have been drawn to believe in Jesus. Whether I am mistaken in this conclusion I do not know; but, at all events, I beg you to accept the volume as a token of my regard, and believe me your very sincere wellwisher in every sense, P. H. GOSSE. H. W. BATES, ESQ. Are you likely to go out again? Accept my best thanks for the beautiful present you have made me, and the warm welcome which you make me on my return to England. You ask me whether I am likely to go out again. I have no intention at present of doing so. Eleven years of tropical residence and travel, devoted to one pursuit, is a sufficient portion of life to be so spent. I have amassed an extensive private collection, and intend to devote at least some years to the study of the species with a view to publishing a Montfauna of the Amazon Valley. With regard to the other topic mentioned in your very kind letter, I must assure you that I think I have pursued, and still do pursue, the investigation of the wonderful and beautiful creatures that people the earth with a spirit of humility, admiration, and reverence. There will be differences of opinion between us, I have no doubt, on mere matters of undemonstrable dogmatic theology, but in the more essential points of true religious feeling and spirit, I hope in anything I may hereafter write and publish, to continue and increase the good opinion you appear to have of me. UP A CREEK IN DEMERARA From The Cornhill Magazine. most agreeable difference in the temperature. It is still hot and steamy, but our eyes are no longer dazzled by the glare. Above, the canopy of foliage meets, branches from either side uniting to form an arcade, through which only diffused light can penetrate. On one side is a large hog-plum tree loaded with fruit, some of which is floating down the stream and affords refreshment to the party. Ir is ten o'clock in the morning, and for two hours past the open river has been like a furnace. The glare is almost blinding as the sun pours down on the mirror-like surface of the water. Our negro boatmen have been paddling since daybreak, and now begin to nod; even the steersman, who should be wide awake, lets the head of the bateau fall off every few minutes as his head Past the first bend we come to androops. The sides of our craft are al- other, where a gap in the forest wall most burning to the touch, and the allows the sunlight to penetrate. Here black skins of the paddlers glisten in in the water is a large clump of crinums the intense light, while we white men - the lilies of Guiana-their dark-green are almost stifled under our umbrellas. foliage and white flowers contrasting One of the negroes begins whistling for with the almost black waters of the a wind, and causes a laugh at the ab- creek. Near these is a bed of giant surdity of expecting anything so grate-arums, their tapering stems twenty feet ful. Earlier in the morning there was high, while palms and marantas fill up a breeze, and the fringe of vegetation the background. Hardly can we apalong the bank of the river threw a little shade, under which we paddled comfortably; but now the breeze has gone, and the shadow of the trees become too narrow to be available. Every one is looking for the mouth of the creek, and urging the paddlers to go a little faster so that we may get a shel ter. With the promise of a schnap the negroes bend forward with a will, singing and keeping time with their paddles, until the bateau skims along and produces a slight movement in the air, which is very grateful in comparison with the utter stagnancy of a minute or two before. Presently we are steered into a little bay from which flows a stream of coffee-colored water, and are informed that this is the mouth of the creek. Immediately in front and on either side towering masses of foliage shut out the view, and at first it looks as if there is no opening. Bushes come down to the water and hanging creepers festoon these with rosy bignonias, yellow allamandas, dipladenias, and the thousand handsome flowers which decorate the edge of the forest. Proceeding onward we find the apparent bay opening into the first bend of the creek, and in a few minutes we are under the trees. At once there is a preciate one vista before we come upon Everywhere the trees shade us overhead and the creek water is deliciously cool. The vast trunks rise up on either side and unite above, so that our craft |