The Zoologist/4th series, vol 5 (1901)/Issue 719/Editorial Gleanings
Mr. W.L. Sclater, the Director of the South African Museum, has contributed an article to the January number of the 'The Educational News' of Cape Town on the "Migration of Birds in South Africa." Mr. Sclater estimates that there are about forty-four birds which migrate from Europe to South Africa.
Passerine Birds.—Golden Oriole, Spotted Flycatcher, Lesser Grey Shrike, Whitethroat, Garden-Warbler, Willow-Wren, Icterine Warbler, Marsh, Great Reed, and Sedge Warblers, Martin, Sand-Martin, Swallow, Yellow Wagtail, Tree-Pipit.
Picarian Birds.—Alpine Swift, Common Swift, Nightjar, Roller, Bee-Eater, and Cuckoo.
Shore Birds and Waders.—Pratincole, Caspian Plover, Ringed Plover, Kentish Plover, Green Plover, Turnstone, Avocet, Stilt, Great Snipe, Sanderling. Little Stint, Curlew-Sandpiper, Knot, Ruff, Common Wood and Green Sandpipers, Redshanks, Greenshanks, Curlew, and Whimbrel.
All these birds are summer visitors, only arriving in September and October, and leaving again in April. In most cases, at any rate, they do not breed in South Africa, although this season is the breeding one for other resident birds; but this is a special point which requires investigation.
One of the best known of these birds is the English Swallow, which must be carefully distinguished from the many other South African Swallows, many of which are resident and breed in South Africa. It may be known by its red forehead and throat, black-blue upper surface and chest-band, and buff-white abdomen. It is found everywhere in South Africa, from Cape Town to the Zambesi, from November to March; but when it arrives, after a journey of over six thousand miles, its plumage is much bleached, the throat is nearly white, and the chest-band pale brown. However, before leaving again for the north, it undergoes a complete spring moult, and sets off on its long journey in a complete new set of feathers.
In Natal Mr. Seebohm has observed that the Swallows remain till the first week in April, while other observers state that they arrive in North Africa during the last half of February, in South Europe during the first half of March, and in Central Europe not until the last half of March. It is perfectly certain that the Natal Swallows, if they only leave during the first half of April, even allowing only a few days in which to accomplish a journey of five thousand to six thousand miles, must go to some part of North Europe or to North-west Asia, since the Swallows which breed further south have arrived at their breeding-grounds before the South African birds have left their winter quarters. So far as it goes, this evidence is conclusive that, in case of the European Swallow, the individuals which go further north to breed go further south in winter.
It has been asserted that some European Swallows remain in South Africa through the greater part of the year, and Andersson even asserts that in some uncivilized parts they affix their nests to some projection of a rock or trunk of a tree. More evidence, however, on this point is required.
Between August and April there can generally be seen about Cape Town and the suburbs large numbers of Black Swifts, flying often at a considerable height above the ground, as is their usual habit. Mr. Layard believed these to be the European Swift, which spends the summer months in Europe, and disappears southwards in August or September. A careful comparison, however, of the European and South African bird seems to show that there are differences between them, the African bird being somewhat larger and darker in colour. Hitherto no authenticated observation on the breeding of the Black Swift in South Africa has been made; but if, as is now supposed to be the case, the South African bird is distinct, it probably does nest somewhere in South Africa, and at any rate the birds from about Cape Town do disappear during the winter months. We do not know where they go to.
Besides the migrants from Europe who come to South Africa to avoid the northern winter, there are a good many birds whose breeding range is in South Africa, and who migrate northwards during the South African winter, probably to Central Africa; about the exact migration range of these birds much less is known than about the movements of the European birds.
Among the more familiar or better known cases are those of the White-throated Swallow, which remains only from August to March; the Pearl-breasted Swallow; the large Stripe-breasted Swallow, one of the most familiar of the group, which generally builds its nest—a retort-shaped chamber entirely constructed of mud pellets—over a porch under the shelter of a verandah. Among other groups are the Carmine-breasted Bee-Eater, only found in north of the Vaal River, and the solitary Cuckoo, commonly known as the "Piet Mijn Vrouw."
All these birds are found in South Africa during the South African summer from September to March, after which date they are seen no longer, but are supposed to retreat northwards, to somewhere in Central Africa, for the southern winter.
We are glad to see that Mr. Herbert Goss has published a second edition, revised, of his 'Geological Antiquity of Insects.' Mr. Goss is thus doing in Britain a similar work to Scudder in America, and entomology, like other branches of zoology, is falling into line in the rejection of the idea that animal life is, or can be, only studied under present appearances. Zittel's 'Grundzüge der Palaeontologie,' which can now be consulted in an English translation, has the Insecta instalment naturally abridged. Mr. Goss has provided a much fuller essay on the subject, which is published at a small cost by Gurney and Jackson. Twenty years have elapsed between the appearance of these two editions, and the author, having put his hand to the plough, should not draw back, but give us a still fuller and more comprehensive work on the subject which he seems to have really made his own in this country.
On the Wheatears (Saxicola) occurring in North America—this question is discussed by Leonhard Stejneger in the 'Proceedings' of the United States National Museum (vol. xxiii. pp. 473-81). The common European Wheatear (Saxicola œnanthe) is a regular breeder in the United States, and Mr. Stejneger, following Degland (1849), Baird(1864), Gould ('Birds of Great Britain'), and more especially Lord Clifton ('Ibis,' 1879), not only recognizes two forms—a larger and smaller—both in Europe and America, but also applies a distinctive name, Saxicola œnanthe leucorhoa, Gmel., to the larger form of the species, which he thus diagnoses:—"Larger than Saxicola œnanthe, the length of wing varying between 100 and 108 millimetres; colour similar, but the rufous tints more bright on the average."
The artificial incubation of Alligator eggs is described by Albert M. Reese in the March number of 'The American Naturalist' (p. 193). The Florida Alligator lays her eggs, about thirty in number, in a so-called nest, which she constructs of sticks, leaves, earth, &c., on the banks of the pond or stream in which she lives. The eggs are laid in the cavity of the nest, and are carefully covered, and allowed to incubate by the heat of the sun. When the young Alligators are about ready to hatch they make a curious squeaking noise, which attracts the mother's attention, and she uncovers the eggs so that the young Alligators may not be smothered in the nest after they escape from the eggs. This fact was confirmed by the artificial batching of a few eggs in an incubator at a temperature of 37° C. On opening the incubator a couple of weeks after the insertion of some well developed eggs "curious squeaking sounds were heard coming from the inside of the eggs, the sounds which in nature tell the mother that her young are about ready to hatch, and should be helped out of the mass of earth and leaves in which they are buried. These sounds are audible at a distance of fifteen yards or more, so that even when the eggs are buried in the nest the parent is probably able to hear the call of her young. The next day after the first sound was heard, one of the Alligators broke out of its shell, and a couple of days later two more hatched.
We have received a Report on the Sarawak Museum, written by Mr. R. Shelford, the Curator, dated February, 1901. Apart from the details of the very satisfactory progress in the growth of this happily situated institution, the most interesting biological information relates to the seasonal variation in the Rhopalocera. Mr. Shelford writes:—
"It is noteworthy that Bornean butterflies do not, to any great extent, exhibit seasonal variation; such species that do are quite irregular in their appearance, e.g. the collection contains a long series of the so-called wet- and dry-season forms of Melanitis ismene (Cr.) which have been caught at all months of the year, and many examples of both forms have been caught in the same month. Neopithecops gaura (Butl.) is equally erratic in variability. It appears probable that the markings and colouration of the images of these variable forms are dependent on the degree of damp or dryness to which the young stages (egg, larva, or pupa) are subjected; if this is indeed the case, a spell of wet weather in the fine monsoon—a by no means unusual event—would produce a crop of wet-season forms, and conversely a spell of fine weather in the wet monsoon a crop of dry-season forms."
Mr. Lionel de Nicéville, who has recently been appointed "Entomologist" to the Indian Museum, Calcutta, has recently published a most valuable paper on "The Food-Plants of the Butterflies of the Kanara District of the Bombay Presidency" (Journ. Asiat. Soc. Bengal, vol. Ixix. pp. 187-278). Apart from food-plants, the larvæ of many butterflies will, when they cannot obtain vegetable food, eat each other, or soft newly-formed pupæ. The Lycænidæ appear to have the distinction in cannibalistic propensities. One larva of Tajura cippus has been known to eat up over a dozen young ones of its own species. The tendency to cannibalism is not confined to the Lycænidæ, but exists also among the Pierinæ; the larvæ of Appias will eat each other, and any other species of larvæ feeding on the same food-plant as themselves, if forced to it by hunger.
In the 'Transactions' of the Hull Scientific and Field Naturalists' Club for the year 1900 (vol. i. No. III) the Secretary, Mr. T. Sheppard, has commenced a series of articles on "Bygone Hull Naturalists," in which the late George Norman (1823-1882) is the subject of the first memoir. Mr. Norman was an old and valued contributor to 'The Zoologist,' contributing no fewer than forty-seven notes between the years 1843 and 1864. An excellent portrait of Norman is given, and memoirs are promised of other Hull naturalists, including Adrian Hardy Haworth, Peter William Watson, Robert Harrison, and William Spence.
The Transactions and Annual Report of the Sheffield Microscopical Society (1899-1900) contain an abstract of a lecture delivered by Dr. H.C. Sorby, on "Improved Methods of Preparing and Preserving Specimens of Marine Animals." The use of glycerine was recommended.
"He found that, in thus treating a species of Nereis worm very common in some of the Essex estuaries, it was possible to dry small specimens and mount them in balsam without any of the minute blood-vessels being obliterated by decomposition. After trying many modifications of this process, the best results were obtained from the following method:—Specimens of the worm, about two or three inches long, were put direct from the sea-water into strong glycerine diluted with an equal volume of water. Here they quickly died, and, after remaining in it for about ten minutes, were seen to be much reduced in size by the transfusion of water into the glycerine. They were then transferred to water, and kept in it for about ten minutes so as to remove most of the glycerine, and to cause them to expand to about their original size. They were then quite limp, and could easily be arranged on microscopic-slide glasses, and were dried as quickly as they could at the usual temperature in the open air, and in doing so became thin, but shrank very little laterally. They were then mounted in balsam, under thin covers, in cells made of thin glass strips. When thus mounted they are not only permanently preserved, but, being made comparatively thin, flat, and transparent, the structure is seen far better than when the animals are alive or recently dead, and the natural red colour of the blood is preserved. When worms are preserved in alcohol or formalin they are rendered opaque, and the blood becomes brown."
In preparing marine animals as museum specimens. Dr. Sorby had had some beautiful results through using strong glycerine. The beautiful natural colours had been, he hoped, permanently preserved. Specimens of Sea-anemones and Star-fish thus preserved were shown, the natural shape of the animals and their delicate tints of colour being much admired.
Mr. J.C. Stevens sold, on April 15th, the library of natural history books formed by the late Mr. Philip Crowley, of Waddon House, Croydon, The following were the highest prices reached:—'Transactions' of the Entomological Society, 46 vols, and 4 parts, £38. 'Catalogue of the Birds in the British Museum,' 27 vols., £48. 'The Ibis,' 1859-1900, £75. 'Proceedings' of the Zoological Society, 1830-1900, £60. Lord Lilford's 'Birds of the British Islands,' 7 vols., £63. 'Biologia Centrali-Americana,' 35 vols., £90. 'Great Auks' Eggs,' 66 plates, £13 4s. Dresser's 'Birds of Europe,' 9 vols., £56. Grandidier's 'Histoire Physique de Madagascar,' 1875-95, £35 14s. Sander's 'Reichenbachia': Orchids, both series, £14. Gould's 'Birds of Asia,' £51. 'Birds of New Guinea,' £45; 'Mammals of Australia,' £29 8s.; 'Birds of Great Britain,' £49 7s. D.G. Elliot's 'Monograph of the Cats,' £10; 'Monograph of the Pheasants,' £53 11s, E.T. Booth's 'Rough Notes on Birds,' £25 4s, G.R. Gray's 'Genera of Birds,' £17 17s.—Athenæeum.
Mr. G.W. Kirkaldy, in the last number of the 'Journal' of the Quekett Microscopical Club (April, 1901), contributes a paper on "The Stridulating Organs of Waterbugs (Rhynchota), especially of Corixidæ."
The Nepidæ, Notonectidæ, and Naucoridæ are very briefly dismissed, as no stridulating organs have yet been discovered in these families, the limæ figured by Swinton some years ago being imaginary. In the Corixidæ the anterior tarsi are highly modified, being thickened and dilated—more or less knife- or spoon-shaped—in both sexes. In all the species of Corixa, there are in the male sex a number of chitinous "pegs" or "teeth" on the inner surface of the flattened tarsi. It was formerly supposed that the stridulation was occasioned by the rubbing of these pegs across the strongly keeled face of the bug. Kirkaldy points out, however, that the pegs exist only in the males, that the peculiar form of face is common to both sexes, and that it is protected by strong bristly hairs, and considers that stridulation is actually caused by the drawing of the pegs on the left (anterior) tarsus across a specially modified area (furnished with minute closely set chitinous points) on the inner side of the opposite femur, or vice versâ. These pegs do not exist in the closely allied genera Micronecta and Cymatia—being replaced by slender bristles—nor is there a specially modified femoral area; and Handlirsch, in a recent paper on the same subject, suggests that the long curved claw of the male in these genera may form part of the musical instrument. The remarkable "strigil" is supposed by Handlirsch to be a stridulating organ, though the present author is sceptical, pointing out that the "musical notes" have only been heard while the bugs are under water, when the abdomen is completely covered by the closely adpressed elytra and wings. It is thought possible that the strigil may be employed while the bugs are on the wing, migrating for mating purposes.