having each a personate, spurred corolla, with didynamous stamens, and are thus readily distinguishable; we may add that, as far as our species are concerned, the blossoms are all of some shade of blue, yellow, or white.

There are six British species of Toadflax sufficiently frequent to merit description; besides one (Linaria pelisseriana) which is confined to Jersey; another, a doubtful native (Linaria supina), which occurs in one or two places in Cornwall, Devon, and Dorset; and a third (Linaria purpurea), formerly much cultivated in gardens, which occasionally strays from them. None of these merit more than this passing notice in a paper which aims rather at instructing in common things than at encouraging the search for rare ones.

We shall find it convenient in this, as in previously considered genera, to divide our six species into groups, for the purpose of more readily considering each; and two very natural ones at once present themselves the first containing three species, with upright stems and narrow leaves; the second, the remaining three, with trailing stems and broadish leaves.

I. The Common Toadflax (Linaria vulgaris) is the handsomest of our British species, and demands our first attention, as to it we are evidently indebted for both the English and Latin names of the genus. It is clear that the name Toadflax was originally bestowed upon this species alone, although it has since been extended to the entire genus. In our old herbals we find the name Toadflax applied especially to Linaria vulgaris, and exclusively to the species with long narrow leaves and upright stems. Mr. Holland thinks that the reason for this may be found in the supposition (that the word toad is prefixed as meaning spurious or false-the name of an unpopular reptile being given to what, at first sight, appeared to be like flax (which Linaria vulgaris certainly does before flowering), but which proved not to be the right thing; just as dog is prefixed to the names of many plants to denote that they are not the genuine article-dog-rose, dog-violet, to wit. That the name Toadflax really means false or spurious flax, he considers is rendered more apparent by the fact that in Cheshire it is applied to the Corn Spurrey (Spergula arvensis), a plant which bears a very superficial resemblance, especially in flower, to the Mountain Flax (Linum catharticum), which is there in immense reputeļas a stomachic herb. Gerarde speaks of Linaria vulgaris as "Wild-fax, Tode-flax, or Flax-weed," which strengthens the above-expressed opinion; although he points to another derivation of the name when he says that the flowers have "a mouth like untoe a frog's mouth"-a somewhat fanciful resemblance, from which the Danish torskmund, or haddockmouth, evidently originates. Linaria vulgaris is more like the Snapdragon than any of the other species,

Mr.

both in the size of its blossoms and in general growth; the flowers are very handsome-pale yellow, with a deep orange palate; the narrow grey-green leaves have been before alluded to. Withering says that cows, horses, and swine refuse to eat them, and that sheep and goats are not fond of them; while the smell of the flowers is obnoxious to flies. Besides the names above mentioned, this species is known as Butter-and-Eggs, Pattens-and-Clogs, Gall-weed, and Wild Snapdragon. It is by no means uncommon throughout England; and although preferring a gravelly soil, is not confined to it: in the north of Scotland it is of rare occurrence. Linaria vulgaris grows chiefly in hedges or the borders of fields. Holland says that "it is almost a sure indicator of an admixture of peat and sand in the soil." The first specimens we ever saw were brought, curiously enough, from the Toad Rock at Tunbridge Wells. It blossoms from June until late autumn.-Our second species, the Creeping, or Pale Blue Toadflax (Linaria repens), is the rarest of the six we are now attempting to describe. The term creeping applies only to the young shoots, as the flowering stems are erect, sometimes attaining, or even exceeding, the height of two feet. The leaves resemble those of Linaria vulgaris, but are shorter; the blossoms are white, tinged with blue or purple, the palate pale yellow, and the upper lip marked with purple lines; they are also slightly fragrant, and smaller than those of the common Toadflax. Ray, who calls this species the "Blue Toadflax, with short and narrow leaves," appears to have first directed attention to it as a British plant, "found by that learned and eminent physician Dr. Eales, in Hartfordshire." One of the best-known stations for the plant, also first noticed in Ray's "Synopsis," is Henley-on-Thames; here it was "found by Mr. Dandridge, on the side of a hill called Marvell Hill, by Henley townside, and by Mr. J. Sherard on the church walls at Henley, and in a field on the left hand the road from London, on a steep bank a little before you come to the town, plentifully." Mr. Stubbs, of Henley, to whom we are indebted for the specimens from which the above description was drawn up, writes that it still "grows profusely on the chalk hills about Henley-noticeably on White or Remenham Hill. I have also met with it on walls, and I believe the upper portion of the south face of the church tower is verdant with it, though the great height from the road will not enable me to speak with certainty. Ray's nomenclature,” he continues, "is obsolete; at least, I have never heard of Marvell Hill." Linaria repens grows on a chalky soil, and is most frequent in the south of England, becoming gradually rarer towards the north, and is seldom, if ever, found in Scotland: it commences to blossom in July;-The Least Toadflax (Linaria minor) differs considerably from the two before described. Linaria vulgaris and Linaria repens are perennials; Linaria

minor is an annual; besides which, the flowers of the former are racemose, while in this species they are solitary, growing in the axils of the leaves. It is a small plant, with a weak but erect stem, much branched, and somewhat clammy, about six inches in height, but often much shorter; the flowers are small and inconspicuous, of a light purple colour, tinged with yellow or white; the leaves are narrow and dark green. The old writers evidently considered this a true Snapdragon; they called it the Least Calf's-snout, or Small Creeping Snapdragon, thus connecting it with Antirrhinum Orontium, which they call the Lesser Calf's-snout, or Snapdragon. It is by no means uncommon in cornfields, or as a weed in gardens; and we have noticed it in two places growing in great profusion between the lines on the railway, a habitat apparently congenial to it. In Macgillivray's arrangement of Withering's British Plants, this species is spoken of as 'rare"; but this statement must be taken with reference to Scotland only, as in England it is very generally distributed, although less frequent towards the north. It blossoms from the end of May until late in the season.

II. We now come to our second group, which contains the three species with procumbent stems and broader leaves; the blossoms of each are also solitary. The first of these is the Ivy-leaved Toadflax (Linaria Cymbalaria), a plant which, originally introduced, has most completely established itself in the land of its adoption. Johnson, in his edition of Gerarde's Herbal (1633), says that it "growes wilde upon walls in Italie, but in gardens with us;" while Ray, in the "Synopsis" (1724), gives only two or three localities for it, mentioning especially the walls of Chelsea Garden, and neighbouring places. It is now, however, common on walls in many parts of England, especially in the neighbourhood of London; it prefers a damp situation, in which the leaves attain great luxuriance. These, as the name of the plant implies, resemble those of the ivy, although very much smaller; they are deep green above, frequently pink or purple beneath, and of a somewhat fleshy texture. The blossoms of this Toadflax, as of the two next species, are axillary, on long footstalks; they are small, pale-blue spotted with yellow and white, and very numerous. The whole plant is very graceful in appearance, especially when, growing on the top of a wall, the long trailing shoots hang down in dense masses on either side. Miss Pratt, in the "Flowering Plants of Great Britain," says that "the capsules, before ripening, turn round towards the wall on which the plant so often grows, and place themselves in a crevice or hole, so as to shed the seeds, when ripened, in a place where they may thrive, instead of scattering them on the ground, where they would be wasted." The fine fibrous roots insinuate themselves so tightly into these crevices, that it is almost impossible

to remove them without breaking. Although an introduced plant, the Ivy-leaved Toadflax has obtained not only "a local habitation," but also "a name"-in fact, two or three; it is popularly called Mother of Thousands, and, less frequently, Pellitory-of-the-Wall, and Maiden-hair. The winter frosts are usually too severe for it, and the leaves then disappear, but it is by nature a perennial; the blossoms peep out about the end of April, and continue until the approach of winter.-Our other two species are known by the English name Fluellin, and have so much in common that they may be appropriately considered together. The Roundleaved Fluellin (Linaria spuria) is a trailing plant with many stems, and grey-green, dusty-looking leaves, mostly alternate, which are usually downy, and round or egg-shaped. The blossom, although small, is extremely beautiful, the lower lip being pale yellow, and the upper deep purple, almost black. The Halbert-leaved, or Sharp-pointed Fluellin (Linaria Elatine), has leaves of the same dusty hue, but they are narrower, longer, halbertshaped, and sharply pointed; the flowers are also like those of Linaria spuria, but smaller, and the purple of the upper lip is of a somewhat lighter shade. Both are annuals, growing in cornfields, and, more rarely, on waste ground, in England and Ireland, preferring, although not confined to, a gravelly soil: Linaria Elatine is the more common. Their blossoms expand in July; but it is not until after harvest that they attract much notice, being previously overshadowed by the waving wheat. We shall often, however, find a stubble-field gay with these two species, in conjunction with the Least Toadflax, the blue and scarlet Pimpernels, the Spreading Bur Parsley, and the Basil Thyme, and many more equally pretty, and hitherto equally overlooked. Although not now used in medicine, the "vertues" of Linaria Elatine seem to be very noteworthy-as the following extract from Gerarde, which we cannot resist quoting, will show. It is "not onely of a singular astringent facultie, but of such singular efficacy to heale spreading and eating cankers, and corrosive ulcers, that its vertue in a manner passeth all credit in these fretting sores, upon sure proofe done unto sundry persons, and especially upon a man whom Pena reporteth to have his nose eaten most grievously with a canker or eating sore, who sent for the Physitions and Chirurgions that were famously knowne to be the best, and they with one consent concluded to cut the said nose off, to preserve the rest of his face: among these Surgeons and Physitions came a poore sorie Barbar, who had no more skill than he had learned by tradition, and yet undertook to cure the patient. This foresaid Barbar, standing in the companie and hearing their determination, desired that he might make triall of an herbe which he had seene his master use for the same purpose, which herbe (Elatine), though he were

ignorant of the name whereby it was called, yet he knew where to fetch it. To be short, this herbe he stamped, and gave the juice of it unto the patient to drinke, and outwardly applied the same plaisterwise, and in very short space perfectly cured the man, and staied the rest of his body from further corruption, which was ready to fall into a leprosie"! Perhaps a little judicious "puffing" would elevate our little Fluellin into a post of honour equally dignified with Parr's Life Pills and Holloway's Ointment; at any rate, here is a testimonial to its "vertues," equal, if not superior, to any produced in favour of the abovenamed compounds.

Before quitting our Toadflaxes, we would just direct attention to a very remarkable malformation which they occasionally present. This form is termed peloria; and in it the mouth of the blossom is closed up, while instead of one spur, there are from two to five: the stamens also are sometimes five in number, and the corolla becomes tubular. It appears to have been first noticed in Linaria vulgaris, in which species it is rare; but modifications of it have been observed in Linaria repens, Linaria minor, Linaria Elatine, and Linaria spuria. Mr. Holland writes that the two last are "very common on the oolitic clays of the Cotteswold Hills around Cirencester, and are both very prone there to have peloria flowers." It is said that the roots of this form, in Linaria vulgaris, if planted in rich soil, will produce blossoms in which the peloria appearance is retained; but in poor soil, they return to the normal appearance. Blossoms are occasionally found with two or three spurs, although otherwise of the usual form.

B.

illustrious Dutch naturalist the name of P. testudo. Like Mr. Thornton, M. Van der Hoeven regarded it as the larva of an aphis of which the adult form was still unknown.

"These brief historical indications form a summary of all that was known about this insect when we on our part undertook some investigations upon it, the results of which we now propose to communicate. We first ascertained that, far from constituting a new genus, or even a distinct species, the Periphyllus is really nothing but the larva of one of the known species of Aphides which live on the maplenamely, Aphis aceris, a brown species which is to be met with during a great part of the year upon the leaves and at the extremities of the young shoots of that tree. But, at the same time that we ascertained this fact, we were set on the track of a most unexpected discovery, constituting a new and very remarkable peculiarity in the development of the animals of this group, already presenting such curious phenomena in connexion with their reproduction.

THE MAPLE, APHIS.?

HAVING had communications on this subject,

it will gratify some of our readers if we furnish the substance of MM. Balbiani and Signoret's remarks in the "Comptes Rendus" of June 17th, as translated and published in the "Annals of Natural History."

"In 1852 an English naturalist, Mr. J. Thornton, indicated, under the name of Phyllophorus testudinatus, an Hemipterous insect which he had found on the leaves of the common maple (Acer campestre), and which he regarded as the larva of an undetermined species of aphis. Subsequently, in 1858, Mr. Lane Clark also observed it, and placed it, under the name of Chelymorpha phyllophora, in a genus intermediate between the Aphidida and the Coccidæ. Lastly, in 1862, M. Van der Hoeven, of Leyden, described it, also as a new genus, replacing the generic names Phyllophorus and Chelymorpha by that of Periphyllus, the other names being previously employed to designate other genera of insects; and our Hemipteron received from the

Fig. 200. Maple Aphis (Aphis aceris), young, magnified.

"This was the faculty, become transmissible to all the generations of a particular species, of engendering two kinds of individuals-one normal, the other abnormal-of which the former alone, after their birth, continue the course of their development, and become capable of reproducing the species; whilst the latter retain throughout their existence the form which they possessed on coming into the world, and appear to be incapable of propagating. Moreover these two categories of individuals present such marked characters that, without having watched their birth, and being thus convinced that they are really produced by identical females, and sometimes even by one and the same mother, one would inevitably consider them to belong to two species, nay even to two completely different genera. Now

one of these is nothing but the Periphyllus mentioned at the commencement of this note as having been described by the authors who had observed it❘ as a separate genus in the family of the Aphides.

Such is, in summary, the singular observation that we have made upon Aphis aceris. We may now give some fuller details upon each of the two kinds of individuals of which this species is composed.

"When we examine with the naked eye or with a lens the embryos of the brown Aphis of the maple at the moment of their being produced by the females, or after opening the bodies of the latter, we see at once that all of them have not the same coloration. In some they are of a tolerably bright green, whilst in others their colour is more or less brownish or greenish-brown. The brown embryos present no peculiarities, and only differ from their mothers by characters analogous to those which are remarked in all species of Aphides between the newly born young individuals and the adult females. As in these latter, their bodies and appendages are furnished with rather long simple hairs, and, like all young Aphides at the moment of their birth, they already contain rudiments of embryos in the interior of their generative apparatus. If, on the other hand, we examine the green embryos, we at once detect, besides their peculiar coloration, very marked differences between them and their brown congeners. The various parts of the body and limbs do not present the same conformation as in the latter, but one is especially struck by the extraordinary development and the unusual appearance of their tegumentary system. Thus their surface is no longer furnished only with simple hairs, but also and principally with scaly transparent lamellæ, more or less rounded or oblong, and traversed by divergent and ramified nervures. These lamellæ occupy especially the anterior margin of the head, the first joint of the antennæ (which is very stout and protuberant), the outer edge of the tibia of the two anterior pairs of legs, and the lateral and posterior margins of the abdomen. Moreover the whole dorsal surface of the latter and of the last thoracic segment is covered with a design having the aspect of a mosaic composed of hexagonal compartments, and which is not without analogy to the pattern formed by the scaly plates of the carapace of tortoises. These peculiarities give our insect a great elegance of appearance, which causes it to be much in request with the amateurs of the microscope in England, where it is commonly known under the name of the 'Leaf-insect.' The entire animal is strongly flattened, and resembles a small scale applied to the surface of the leaf upon which it reposes, and on which it requires a certain amount of care to detect it.

"Another remarkable character of these abnormal individuals of Aphis aceris is the rudimentary

state of their generative apparatus. This is reduced to a few groups of small pale and scarcely visible cells, none of which arrives at maturity to become transformed into an embryo; and it retains this character as long as it is possible to observe the animal. The functions of nutrition, also, are performed in them in a very unenergetic manner; for from the moment of their birth until that at which we cease to observe them, they increase but little in size, attaining scarcely one millimetre. They undergo no change of skin, never acquire wings like the reproductive individuals, and their antennæ always retain the five joints which they present in all young Aphides before the first moult. Nevertheless they possess a well-developed rostrum and an intestinal canal, the peristaltic contractions of which we have distinctly observed. In short, although we have observed them for several months (that is to say, from May to November), no change in their condition was ascertained; and they disappeared with the leaves which bear them, without its being possible to ascertain what becomes of them subsequently.

"The question naturally arose, What was the signification of these abnormal individuals of the Aphis of the maple, and what part did they fulfil in the reproductive functions of the species to which they belong? They are evidently not males, since their generative apparatus retains the same rudimentary form at whatever epoch we examine them. Moreover in no known species of Aphis are the males produced at the same time as the viviparous individuals, which are not the true females of the species. There is therefore no other alternative but to regard them as a modification of the specific type constantly reproduced with the same characters by the successive normal generations. Our abnormal Aphides are indeed deprived of the faculty of reproduction, either by sexual generation or in any other manner; but after the observations of M. H. Landois upon the law of sexual development in insects, we know that in them the sexes depend simply upon the conditions of alimentation of the larva. Because, in the present state of things, these conditions have not yet occurred for one of the two sorts of larvæ of Aphis aceris, there is no reason for our concluding that they may not some day be realized; and by thus acquiring, with the attributes of the sexes, the faculty of propagating directly in an indefinite manner, these abnormal individuals will become in their turn the origin of a new species produced by deviation from an anterior specific type."

CONTRARY TO NATURE.-The truth is that folks' fancy that such and such things cannot be, simply because they have not seen them, is worth no more than a savage's fancy that there cannot be such a thing as a locomotive, because he never saw one running wild in the forest.-Water Babies.

"HAIRS OF DERMESTES."

much lighter in colour than those from the other insect, in which they are of a deep brown. This

we were subjected for using the above title on a former occasion, we have adopted it again, because, though not absolutely correct, it is sufficiently so for such a purpose, and having used it before, it is advisable not to change it upon resuming the same subject. Mr. S. J. M'Intire, who has already contributed towards clearing the mystery which enshrouded the source of the so-called "hairs of Dermestes," during last month sent us the following communication:

"I enclose two specimens of beetles bred from larvæ producing the hairs known as 'Hairs of Dermestes.' The larger is the insect referred to in my article in S.G., vol. i., page 230, and the smaller one, which is a very pretty microscopic object (being covered with scales like the Curculio family) is from larvæ found by Frank Blatch, Esq, in a wood-shed on his premises at Theale, Berks. The individuals he sent me, as well as the larvæ from under the elm-tree bark, fed while I kept them, upon the dried-up remains of a butterfly, until they completed their transformations. Perhaps you will kindly name both insects for the benefit of those interested in the subject which has occupied some space in the pages of SCIENCE-Gossip.”

In consequence of this letter we wrote requesting to be informed more minutely on certain particulars ragarding these insects, which were embodied in a second letter communicated to us by the same gentleman.

"1. The larvæ of the large beetle were found under the bark of an elm-tree at Ealing. One or two small specimens that I obtained at the same time have lived with me ever since and have grown considerably; they have also cast their skins, and the halbert-shaped hairs on the new skins are far more numerous than on the old ones. I have fed them on entomological specimens. They seldom feed while under microscopical observation, but that they devour the food I have given them when shut up in the dark is obvious.

"2. The first larva of the small beetle that my friend Mr. Batch sent me was found entangled in a spider's web. Others he has since found on the door, and various places besides in the same shed; and the perfect insects he obtains on the slabs. I think they fed while I kept them on the body of a hawk-moth; at all events they took refuge in its body, and effected their final change while inside it.

"3. I send the exuvia of both insects mounted temporarily to admit of close examination, and I think you will find that there are hairs attached still to both skins.

"I notice that the elm-tree larvæ hairs are very

when the halbert-shaped hairs are very abundant."

All that now remains for us to do is to give a figure of the large beetle magnified (fig. 201), which certainly appears to be Tiresias serra, the larvæ and hairs of which do not differ from those figured from Mr. M'Intire's drawings in SCIENCEGOSSIP for 1865, p. 230 (fig. 202).

The smaller beetle corresponds with Anthrenus varius, the hairs from the larvæ of which are now figured for comparison with those derived from the larvæ of the larger beetle (fig. 203). We have before affirmed our belief that hairs, scarcely distinguishable from each other, might be obtained from several of the Dermestidæ, and perhaps also from the allied family of Mycetophagidæ, and we do not suppose by any means that Tiresias serra, Anthrenus varius, and Anthrenus muscorum are the only beetles the larvæ of which yield the beautiful hairs long known under the name of "Hairs of Dermestes." Mr. S. J. M'Intire deserves thanks for his patient pursuit of this inquiry to a successful termination.

IN

THE CHOLERA FUNGUS.

N the Standard of August 27th is an important communication on this subject, from which we are only able, at this late period, to give the following extract:

"In the report of the medical officer of the Privy Council just issued, an account is given of some remarkable researches of Professor Hallier on this important subject. Hallier believes that he has discovered the active agent which causes cholera. In examining the contents of the bowels in cholera, this observer has noticed a very large amount of a vegetable fungus in the shape of cells (or seed) and filaments (or roots, as they may be termed). The cells attach themselves to the remnants of any food,