Chapter VII: Appendix

Gemiasma verdans and Gemiasma rubra collected Sept. 10, 1882, on Washington Heights, near High Bridge. The illustrations show the manner in which the mature plants discharge their contents.

Plate VIII. A, B, and C represent very large plants of the Gemiasma verdans. A represents a mature plant. B represents the same plant, discharging its spores and spermatia through a small opening in the cell walls. The discharge is quite rapid but not continuous, being spasmodic, as if caused by intermittent contractions in the cell walls. The discharge begins suddenly and with considerable force--a sort of explosion which projects a portion of the contents rapidly and to quite a little distance. This goes on for a few seconds, and then the cell is at rest for a few seconds, when the contractions and explosions begin again and go on as before. Under ordinary conditions it takes a plant from half an hour to an hour to deliver itself. It is about two-thirds emptied. C represents the mature plant, entirely emptied of its spore contents, there remaining inside only a few actively moving spermatia, which are slowly escaping. The spermatia differ from the spores and young plants in being smaller, and of possessing the power of moving and tumbling about rapidly, while the spores of young plants are larger and quiescent. D, E, F, and G represent mature plants belonging to the Gemiasma rubra. D represents a ripe plant, filled with spores, embryonic plants, and spermatia. E represents a ripe plant in the act of discharging its contents, it being about half emptied. F represents a ripe plant after its spore and embryonic plant contents are all discharged, leaving behind only a few actively moving spermatia, which are slowly escaping. G represents the emptied plant in a quiescent state.

Figs. A, B, C represent an unusually large variety of the Gemiasma verdans. This species is usually about the size of the rubra. This large variety was found on the upper part of New York Island, near High Bridge, in a natural depression where the water stands most of the year, except in July, August, and September, when it becomes an area of drying, cracked mud two hundred feet across. As the mud dries these plants develop in great profusion, giving an appearance to the surface as if covered thickly with brick dust.

These depressions and swaily places, holding water part of the year, and becoming dry during the malarial season, can be easily dried by means of covered drains, and grassed or sodded over, when they will cease to grow; this vegetation and ague in such localities will disappear.

The malarial vegetations begin to develop moderately in July, but do not spring forth abundantly enough to do much damage till about the middle of August, when they in ague localities spring into existence in vast multitudes, and continue to develop in great profusion till frost comes.

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ANALYSIS OF THE MALARIA PLANT (GEMIASMA RUBRA).

By Prof Paulus F. Reinsch.

Author Algæ of France, 1866; Latest Observations on Algology, 1867; Chemical Investigation of the Connections of the Lias and Jura Formations, 1859; Chemical Investigation of the Viscum Album, 1860; Contributions to Algology and Fungology, 1874-75, vol. i.; New Investigation of the Microscopic Structure of Pit Coal, 1881; Micrographic Photographs of the Structure and Composition of Pit Coal, 1888.

Dr. Cutter writes me September 28, 1882: "My dear Professor: By this mail I send you a specimen of the Gemiasma rubra of Salisbury, described in 1862, as found in bogs, mud holes, and marshes of ague districts, in the air suspended at night, in the sputa, blood, and urine, and on the skin of persons suffering with ague. It is regarded as one of the Palmellaceæ. This rubra is found in the more malignant and fatal types of the disease. I have found it in all the habitats described by Dr. Salisbury. Both he and myself would like you to examine and hear what you have to say about it."

The substance of clayish soil contains, besides fragments of shells of larger diatoms (Suriella synhedra), shells of Navicula minutissima, Pinnularia viridis. Spores belonging to various cryptogams.

1. Spherical transparent spores with laminated covering and dark nucleus--0.022 millimeter in diameter.

2. Spherical spores with thick covering of granulated surface.

3. Spherical spores with punctulated surface--0.007 millimeter in diameter.

4. Very minute, transparent, bluish-greenish colored spores, with thin covering and finely granulated contents--0.006 millimeter in diameter.

5. Chroococcoid cells with two larger nuclei--0.0031 millimeter in diameter. Sometimes biciliated minute cells are found; without any doubt they are zoospores derived from any algoid or fungoid species.

I cannot say whether there exists any genetic connection between these various sorts of spores. It seems to me that probably numbers 1-4 represent resting states of the hyphomycetes.

No. 5 represents one and two celled states of chroococcus species belong to Chroococcus minutus.

The crust of the clayish earth is covered with a reddish brown covering of about half a millimeter in thickness. This covering proves to be composed, under the microscope, of cellular filaments and various shaped bodies of various composition. They are made up of cells with densely and coarsely granulated reddish colored contents--shape, size, and composition are very variable, as shown in the figures. _The cellular bodies make up the essential organic part of the clayish substance, and, without any doubt, if anything of the organic compounds of the substance is in genetical connection with the disease, these bodies would have this role_. The structure and coloration of cell contents exhibit the closest alliance to the characteristics of the division of Chroolepideæ and of this small division of Chlorophyllaceous Algæ, nearest to Gongrosira--a genus whose five to six species are inhabitants of fresh water, mostly attached to various minute aquatic Algæ and mosses. Each cell of all the plants of this genus produces a large number of mobile cells--zoospores.

Fig. 9 represents very probably one zoospore developed from these plants as figured from 10 to 16.

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CARBON.

M. Berthelot, in the _Journal de Pharmacie et de Chimie_ for March, states that from peculiar physical relations he is led to suspect that the true element carbon is unknown, and that diamond and graphite are substances of a different order. Elementary carbon ought to be gaseous at the ordinary temperature, and the various kinds of carbon which occur in nature are in reality polymerized products of the true element carbon. Spectrum analysis is thought to confirm this view; and it is supposed the second spectrum seen in a Geissler tube belongs to gaseous carbon. This spectrum, which has been recognized along with that of hydrogen in the light of the tails of comets, indicates a carbide, probably acetylene.

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CANNED MEATS.

By P. CARLES.

When tinned iron serves for containing alimentary matters, it is essential that the tin employed should be free from lead. The latter metal is rapidly oxidized on the surface and is dissolved in this form in the neutral acids of vegetables, meat, etc. The most exact method of demonstrating the presence of lead consists in treating the alloy--so-called tin--with _aqua regia_ containing relatively little nitric acid. The whole dissolves; the excess of acid is driven off by evaporation at a boiling heat, and the residue, diluted with water, is saturated with hydrogen sulphide. The iron remains in solution, while the mixed lead and tin sulphides precipitated are allowed to digest for a long time in an alkaline sulphide. The tin sulphide only dissolves; it is filtered off and converted into stannic acid, while the lead sulphide is transformed into sulphate and weighed as such.

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NEW BLEACHING PROCESS, WITH REGENERATION OF THE BATHS USED.

By MR. BONNEVILLE.

To a cold solution containing 1 per cent. of bromine, 1 per cent. of caustic soda at 36° B. is added, then the material, to be bleached is first wet and then immersed in this bath until completely decolorized. It is passed into a newly-acidulated bath, rinsed, and dried. After the bromine bath has been used up, it is regenerated by adding 1 per cent. of sulphuric acid, which liberates the bromine. To the same bath caustic soda is added, which regenerates the hypobromite of soda. The hydrofluosilicic acid can be used, instead of the sulphuric acid, with greater advantage. A bath used up can also be regenerated by means of the electric current.

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DETECTION OF MAGENTA, ARCHIL, AND CUDBEAR IN WINE.

These colors are not suitable for converting white wine into red, but they can be used for giving wines a faint red tint, for darkening pale red wines, and in making up a factitious bouquet essence, which is added to red wines. The most suitable methods for the detection of magenta are those given by Romei and Falieres-Ritter. If a wine colored with archil and one colored with cudbear are treated treated according to Romei's method, the former gives, with basic lead acetate, a blue, and the latter a fine violet precipitate. The filtrate, if shaken up with amylic alcohol, gives it in either case a red color. A knowledge of this fact is important, or it may be mistaken for magenta. The behavior of the amylic alcohol, thus colored red, with hydrochloric acid and ammonia is characteristic. If the red color is due to magenta, it is destroyed by both these reagents, while hydrocholoric acid does not decolorize the solutions of archil and cudbear, and ammonia turns their red color to a purple violet. If the wine is examined according to the Falieres-Ritter method in presence of magenta, ether, when shaken up with the wine, previously rendered ammoniacal, remains colorless, while if archil or cudbear is present the ether is colored red. Wartha has made a convenient modification in the Falieres-Ritter method by adding ammonia and ether to the concentrated wine while still warm. If the red color of the wool is due to archil or cudbear, it is extracted by hydrochloric acid, which is colored red. Ammonia turns the color to a purple violet. König mixed 50 c.c. wine with ammonia in slight excess, and places in the mixture about one-half grm. clean white woolen yarn. The whole is then boiled in a flask until all the alcohol and the excess of ammonia are driven off. The wool taken out of the liquid and purified by washing in water and wringing is moistened in a test-tube with pure potassa lye at 10 per cent. It is carefully heated till the wool is completely dissolved, and the solution, when cold, is mixed first with half its volume of pure alcohol, upon which is carefully poured the same volume of ether, and the whole is shaken. The stratum of ether decanted off is mixed in a test-tube with a drop of acetic acid. A red color appears if the slightest trace of magenta is present. The shaking must not be too violent, lest an emulsion should be formed. If the wine is colored with archil, on prolonged heating, after the addition of ammonia, it is decolorized. If it is then let cool and shaken a little, the red color returns. If the wool is taken out of the hot liquid after the red color has disappeared, and exposed to the air, it takes a red color. But if it is quickly taken out of the liquid and at once washed, there remains merely a trace of color in the wool. If these precautions are observed, magenta can be distinguished from archil with certainty according to König's method. As the coloring-matter of archil is not precipitated by baryta and magnesia, but changed to a purple, the baryta method, recommended by Pasteur, Balard, and Wurtz, and the magnesia test, are useless. Magenta may in course of time be removed by the precipitates formed in the wine. It is therefore necessary to test not merely the clear liquid, but the sediment, if any.--_Dr. B. Haas, in Budermann's Centralblatt.--Analyst_.

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PANAX VICTORIÆ.

Panax Victoriæ is a compact and charming plant, which sends up numbers of stems from the bottom in place of continually growing upward and thus becoming ungainly; it bears a profusion of elegantly curled, tasseled, and variegated foliage, very catching to the eye, and unlike any of its predecessors. The other, P. dumosum, is of similar habit, the foliage being crested and fringed after the manner of some of our rare crested ferns.--_The Gardeners' Chronicle_.

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A NOTE ON SAP.

[Footnote: Read at an evening meeting of the Pharmaceutical Society, London, April 4, 1883.]

By Professor ATTFIELD, F.R.S.

Beneath a white birch tree growing in my garden I noticed, yesterday evening, a very wet place on the gravel path, the water of which was obviously being fed by the cut extremity of a branch of the birch about an inch in diameter and some ten feet from the ground. I afterward found that exactly fifteen days ago circumstances rendered necessary the removal of the portion of the branch which hung over the path, 4 or 5 feet being still left on the tree. The water or sap was dropping fast from the branch, at the rate of sixteen large drops per minute, each drop twice or thrice the size of a "minim," and neither catkins nor leaves had yet expanded. I decided that some interest would attach to a determination both of the rate of flow of the fluid and of its chemical composition, especially at such a stage of the tree's life.

A bottle was at once so suspended beneath the wound as to catch the whole of the exuding sap. It caught nearly 5 fluid ounces between eight and nine o'clock. During the succeeding eleven hours of the night 44 fluid ounces were collected, an average of 4 ounces per hour. From 8:15 to 9:15 this morning, very nearly 7 ounces were obtained. From 9:15 to 10:15, with bright sunshine, 8 ounces. From 10:15 until 8:15 this evening the hourly record kept by my son Harvey shows that the amount during that time has slowly diminished from 8 to a little below 7 ounces per hour. Apparently the flow is faster in sunshine than in shade, and by day than by night.

It would seem, therefore, that this slender tree, with a stem which at the ground is only 7 inches in diameter, having a height of 39 feet, and before it has any expanded leaves from whose united surfaces large amounts of water might evaporate, is able to draw from the ground about 4 liters, or seven-eighths of a gallon of fluid every twenty-four hours. That at all events was the amount flowing from this open tap in its water system. Even the topmost branches of the tree had not become, during the fifteen days, abnormally flaccid, so that, apparently, no drainage of fluid from the upper portion of the tree had been taking place. For a fortnight the tree apparently had been drawing, pumping, sucking--I know not what word to use--nearly a gallon of fluid daily from the soil in the neigborhood of its roots. This soil had only an ordinary degree of dampness. It was not wet, still less was there any actually fluid water to be seen. Indeed, usually all the adjacent soil is of a dry kind, for we are on the plateau of a hill 265 feet above the sea, and the level of the local water reservoir into which our wells dip is about 80 feet below the surface. My gardener tells me that the tree has been "bleeding" at about the same rate for fourteen of the fifteen days, the first day the branch becoming only somewhat damp. During the earlier part of that time we had frosts at night, and sunshine, but with extremely cold winds, during the days. At one time the exuding sap gave, I am told by two different observers, icicles a foot long. A much warmer, almost summer, temperature has prevailed during the past three days, and no wind. This morning the temperature of the sap as it escaped was constant at 52° F., while that of the surrounding air was varying considerably.

The collected sap was a clear, bright, water-like fluid. After a pint had stood aside for twelve hours, there was the merest trace of a sediment at the bottom of the vessel. The microscope showed this to consist of parenchymatous cells, with here and there a group of the wheel-like or radiating cells which botanists, I think, term sphere-crystals. The sap was slightly heavier than water, in the proportion of 1,005 to 1,000. It had a faintly sweet taste and a very slight aromatic odor.

Chemical analysis showed that this sap consisted of 99 parts of pure water with 1 part of dissolved solid matter. Eleven-twelfths of the latter were sugar.

That the birch readily yields its sap when the wood is wounded is well known. Philipps, quoted by Sowerby, says:

"Even afflictive birch,
Cursed by unlettered youth, distills,
A limpid current from her wounded bark,
Profuse of nursing sap."

And that birch sap contains sugar is known, the peasants of many countries, especially Russia, being well acquainted with the art of making birch wine by fermenting its saccharine juice.

But I find no hourly or daily record of the amount of sugar-bearing sap which can be drawn from the birch, or from any tree, before it has acquired its great digesting or rather developing and transpiring apparatus--its leaf system. And I do not know of any extended chemical analysis of sap either of the birch, or other tree.

Besides sugar, which is present in this sap to the extent of 616 grains--nearly an ounce and a half--per gallon, there are present a mere trace of mucilage; no starch; no tannin; 3½ grains per gallon of ammoniacal salts yielding 10 per cent. of nitrogen; 3 grains of albuminoid matter yielding 10 per cent. of nitrogen; a distinct trace of nitrites; 7.4 grains of nitrates containing 17 per cent. of nitrogen; no chlorides, or the merest trace; no sulphates; no sodium salts; a little of potassium salts; much phosphate and organic salts of calcium; and some similar magnesian compounds. These calcareous and magnesian substances yield an ash when the sap is evaporated to dryness and the sugar and other organic matter burnt away, the amount of this residual matter being exactly 50 grains per gallon. The sap contained no peroxide of hydrogen. It was faintly if at all acid. It held in solution a ferment capable of converting starch into sugar. Exposed to the air it soon swarmed with bacteria, its sugar being changed to alcohol.

A teaspoonful or two of, say, apple juice, and a tablespoonful of sugar put into a gallon of such rather hard well-water as we have in our chalky district, would very fairly represent this specimen of the sap of the silver birch. Indeed, in the phraseology of a water-analyst, I may say that the sap itself has 25 degrees of total, permanent hardness.

How long the tree would continue to yield such a flow of sap I cannot say; probably until the store of sugar it manufactured last summer to feed its young buds this spring was exhausted. Even within twenty-four hours the sugar has slightly diminished in proportion in the fluid.

Whether or not this little note throws a single ray of light on the much debated question of the cause of the rise of sap in plants I must leave to botanists to decide. I cannot hope that it does, for Julius Sachs, than whom no one appears to have more carefully considered the subject, says, at page 677 of the recently published English translation of his textbook of botany, that "although the movements of water in plants have been copiously investigated and discussed for nearly two hundred years, it is nevertheless still impossible to give a satisfactory and deductive account of the mode of operation of these movements in detail." As a chemist and physicist myself, knowing something about capillary attraction, exosmose, endosmose, atmospheric pressure, and gravitation generally, and the movements caused by chemical attraction, I am afraid I must concur in the opinion that we do not yet know the real ultimate cause or causes of the rise of sap in plants.

Ashlands, Watford, Herts.

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THE CROW.

[Footnote: Abstract of a recent discussion before the Connecticut State Board of Agriculture.]

Prof. W. A. Stearns, in a lecture upon the utility of birds in agriculture, stated that the few facts we do know regarding the matter have been obtained more through the direct experience of those who have stumbled on the facts they relate than those who have made any special study of the matter. One great difficulty has been that people looked too far and studied too deeply for facts which were right before them. For instance, people are well acquainted with the fact that hawks, becoming bold, pounce down upon and carry off chickens from the hen-yards and eat them. How many are acquainted with the fact that in hard winters, when pressed for food, crows do this likewise? But what does this signify? Simply that the crow regulates its food from necessity, not from choice.

Now, carry this fact into operation in the spring into the cornfield. Do you suppose that the crow, being hungry, and dropping into a field of corn wherein is abundance to satisfy his desires, stops, as many affirm, to pick out only those kernels which are affected with mildew, larva, or weevil? Does he instinctively know what corns, when three or four inches beneath the ground, are thus affected? Not a bit of it. To him, a strictly grain-feeding and not an insect-eating bird, the necessity takes the place of the choice. He is hungry; the means of satisfying his hunger are at hand. He naturally drops down in the first cornfield he sees, calls all his neighbors to the feast, and then roots up and swallows all the kernels until he can hold no more. There is no doubt the crow is a damage to the agriculturist. He preys upon the cornfield and eats the corn indiscriminately, whether there are any insects or not. That has been proved by dissection of stomach and crop.

If corn can be protected by tarring, so that the crows will not eat it, they will prove a benefit by leaving the corn and picking up grubs in the field. Where corn has been tarred, I have never known the crows to touch it.

Mr. Sedgwick remarked that, in addition to destroying the corn crop, the crow was also very destructive of the eggs of other birds. Last spring I watched a pair of crows flying through an orchard, and in several instances saw them fly into birds' nests, take out the eggs, and then go on around the field.

In answer to Mr. Hubbard, who claimed the crow would eat animal food in any form, and might not be rightly classified as a grain-eating bird, Prof. Stearns said the crow was thus classified by reason of the structure of its crop being similar to that of the finches, the blackbird, the sparrows, and other seed-eating birds.

Mr. Wetherell said: Crows are greedy devourers of the white worm, which sometimes destroys acres of grass. As a grub eater, the crow deserves much praise. The crow is the scavenger of the bird family, eating anything and everything, whether it is sweet or carrion. The only quarrel I have with the crow is because it destroys the eggs and young birds.

Mr. Lockwood described the experience of a neighbor who planted corn after tarring it. This seemed to prevent the ravages of the crows until the second hoeing, when the corn was up some eighteen inches, at which time the crows came in and pulled nearly an acre clean.

Crows, said Dr. Riggs, have no crop, like a great many carnivorous birds. The passage leading from the mouth goes directly to the gizzard, something like the duck. The duck has no crop, yet the passage leading from the mouth to the gizzard in the duck becomes considerably enlarged. In the crow there is no enlargement of this passage, and everything passes directly into the gizzard, where it is digested.

Dr. Riggs had raised corn and watched the operations of the crows. Going upon the field in less than a minute after the crows had left it, he found they had pulled the corn, hill after hill, marching from one hill to the other. Not until the corn had become softened and had come up would they molest it. In the fall they would come in droves on to a field of corn, where it is in stacks, pick out the corn from the husks, and put it into their gizzards. They raid robbins' nests and swallows' nests, devouring eggs and young birds. Yet crows are great scavengers. In the spring they get a great many insects and moths from the ground, and do good work in picking up those large white grubs with red heads that work such destruction in some of our mowing fields.

Mr. Pratt stated that he had used coal tar on his seed corn for five or six years, and had never a spear pulled by the crows. Dr. Riggs never had known a crow to touch corn after it got to the second tier of leaves. Mr. Lockwood said crows would sample a whole field of corn to find corn not tarred. Mr. Pratt recommended to pour boiling water on the corn before applying the tar. A large tablespoonful of tar will color a pail of water.

According to Dr. Riggs, the hot mixture with the corn must be stirred continually; if not, the life of the corn will be killed and germination prevented. It may be poured on very hot, if the stirring is kept up and too much tar is not used. If the water is hot it will dissolve the tar, and as it is poured on it will coat every kernel of corn. If the water is allowed to stand upon the corn any great length of time, the chit of the corn will be damaged. The liquid should be poured off and the corn allowed to cool immediately after a good stirring.

Mr. Gold had known of crows pulling corn after the second hoeing, when the scare-crows had been removed from the field. The corn thus pulled had reached pretty good size. This pulling must have been done from sheer malice on the part of the crows.

Mr. Ayer was inclined to befriend the crow. For five years he had planted from eight to twelve acres of corn each year and had not lost twenty hills by crows. He does not use tar, but does not allow himself to go out of a newly-planted cornfield without first stretching a string around it on high poles and also providing a wind-mill with a little rattle box on it to make a noise. With him this practice keeps the crows away.

Mr. Goodwin thought crows were scavengers of the forests and did good service in destroying the worms, grubs, and insects that preyed upon our trees. He had raised some forty crops of corn, and whenever he had thoroughly twined it at the time of planting, crows did not pull it up. In damp spots, during the wet time and after his twine was down, he had known crows to pull up corn that was seven or eight inches high.

Respecting crows as insect eaters, Prof. Stearns admitted that they did devour insects; he had seen them eat insects on pear trees. Tame crows at his home had been watched while eating insects, yet a crow will eat corn a great deal quicker than he will eat insects.--_Boston Cultivator_.

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THE PRAYING MANTIS AND ITS ALLIES.

On examining the strange forms shown in the accompanying engraving, many persons would suppose they were looking at exotic insects. Although this is true for many species of this group, which are indigenous to warm countries, and reach at the most only the southern temperate zone, yet there are certain of these insects that are beginning to be found in France, to the south of the Loire, and that are always too rare, since, being exclusively feeders on living prey, they prove useful aids to us.

These insects belong among the orthoptera--an order including species whose transformations are less complete than in other groups, and whose larval and pupal forms are very active, and closely resemble the imago. Two pairs of large wings characterize the adult state, the first pair of which are somewhat thickened to protect the broad, net-veined hinder pair, which fold up like a fan upon the abdomen. The hind legs are large and adapted for leaping.

The raptorial group called _Mantidæ_, which forms the subject of this article, includes species that maybe easily recognized by their large size, their enormous, spinous fore legs, which are adapted for seizing other insects, and from their devotional attitude when watching their prey.

These insects exhibit in general the phenomenon of mimicry, or adaptation for protection, through their color and form, some being green, like the plants upon which they live, others yellowish or grayish, and others brownish like dead leaves.

In the best known species, _Mantis religiosa_, the head is triangular, the eyes large, the prothorax very long, and the body narrowed and lengthened; the anterior feet are armed with hooks and spines, and the shanks are capable of being doubled up on the under side of the thighs. When at rest it sits upon the four posterior legs, with the head and prothorax nearly erect, and the anterior feet folded backward. The female insect attains a length of 54 millimeters, and the male only 40.

The color is of a handsome green, sometimes yellow, or of a yellowish red. The insects are slow in their motions, waiting on the branches of trees and shrubs for some other insect to pass within their reach, when they seize and hold it with the anterior feet, and tear it to pieces. They are very voracious, and sometimes prey upon each other. Their eggs are deposited in two long rows, protected by a parchment-like envelope, and attached to the stalk of a plant. The nymph is as voracious as the perfect insect, from which it differs principally in the less developed wings.

The devotional attitude of these insects when watching for their prey--their fore legs being elevated and joined in a supplicating manner--has given them in English the popular names of "soothsayer," "prophet," and "praying mantis," in French, "prie-Dieu," in Portuguese, "louva-Deos," etc. According to Sparmann, the Nubians and Hottentots regard mantides as tutelary divinities, and worship them as such. A monkish legend tells us that Saint Francis Xavier, having perceived a mantis holding its legs toward heaven, ordered it to sing the praises of God, when immediately the insect struck up one of the most exemplary of canticles! Pison, in his "Natural History of the East Indies," makes use of the word _Vates_ (divine) to designate these insects, and speaks of that superstition, common to both Christians and heathens, that assigns to them the gifts of prophecy and divination. The habit that the mantis has of first stretching out one fore leg, and then the other, and of preserving such a position for some little time, has also led to the belief among the illiterate that it is in the act, in such cases, of pointing out the road to the passer by.

The old naturalist, Moufet, in his _Theatrum Insectorum_ (London, 1634), says of the praying mantis (_M. religiosa_) that it is reported so divine that if a child asks his way of it, it will show him the right road by stretching out its leg, and that it will rarely or never deceive him.

This group of insects is most abundant in the tropical regions of Africa, South America, and India, but some species are found in the warmer parts of North America, Europe, and Australia. The American species is the "race-horse" (_M. carolina_), and occurs in the Southern and Western States. Burmeister says that _M. argentina_, of Buenos Ayres, seizes and eats small birds.

The genera allied to _Mantis--Vates, Empusa, Harpax_, and _Schizocephala_--occur in the tropics. The genus _Eremophila_ inhabits the deserts of Northern Africa, where it resembles the sand in color.

The species shown in the engraving (which we borrow from _La Nature_) inhabit France.

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MAY-FLIES.

There are usually found in the month of June, especially near water, certain insects that are called Ephemera, and which long ago acquired true celebrity, and furnished material for comparison to poets and philosophers. Indeed, in the adult state they live but one day, a fact that has given them their name. They appear for a few hours, fluttering about in the rays of a sun whose setting they are not to see, as they live during the space of a single twilight only. These insects have very short antennæ, an imperfect mouth incapable of taking food, and delicate, gauze like wings, the posterior ones of which are always small, or even rudimentary or wanting. Their legs are very delicate--the anterior ones very long--and their abdomen terminates in two or three long articulated filaments. One character, which is unique among insects, is peculiar to Ephemerids; the adults issuing from the pupal envelope undergo still another moult in divesting themselves of a thin pellicle that covers the body, wings, and other appendages. This is what is called the _subimago_, and precedes the imago or perfect state of the insect. The short life of adult May-flies is, with most of them, passed in a continual state of agitation. They are seen rising vertically in a straight line, their long fore-legs stretched out like antennæ, and serving to balance the posterior part of the body and the filaments of the abdomen during flight. On reaching a certain height they allow themselves to descend, stretching out while doing so their long wings and tail, which then serve as a parachute. Then a rapid working of these organs suddenly changes the direction of the motion, and they begin to ascend again. Coupling takes place during these aerial dances. Soon afterward the females approach the surface of the water and lay therein their eggs, spreading them out the while with the caudal filaments, or else depositing them all together in one mass that falls to the bottom.

These insects seek the light, and are attracted by an artificial one, describing concentric circles around it and finally falling into it and being burnt up. Their bodies on falling into the water constitute a food which is eagerly sought by fishes, and which is made use of by fishermen as a bait.

But the above is not the only state of Ephemerids, for their entire existence really lasts a year. Linnæus has thus summed up the total life of these little creatures: "The larvæ swim in water; and, in becoming winged insects, have only the shortest kind of joy, for they often celebrate in a single day their wedding, parturition, and funeral obsequies." The eggs, in fact, give birth to more or less elongated larvæ, which are always provided with three filaments at the end of the abdomen, and which breathe the oxygen dissolved in the water by tracheo-branchiæ along the sides of the body. They are carnivorous, and live on small animal prey. The most recent authors who have studied them are Mr. Eaton, in England, and Mr. Vayssiere, of the Faculte des Sciences, at Marseilles.

_A propos_ of the larvæ of Ephemera or May-flies, we must speak of one of the entomological rarities of France, the nature and zoological place of which it has taken more than a century to demonstrate. Geoffroy, the old historian of the insects of the vicinity of Paris, was the first to find in the waters of the Seine a small animal resembling one of the Daphnids. This animal has six short and slender thoracic legs, which terminate in a hook and are borne on the under side of the cephalic shield. This latter is provided above with two slender six-jointed antennæ, two very large faceted eyes at the side, and three ocelli forming a triangle. The large thoraceo-abdominal shield is hollowed out behind into two movable valves which cover the first five segments of the abdomen (Fig. 1). The last four segments, of decreasing breadth, are retractile beneath the carapax, as is also the broad plume that terminates them, and which is formed of three short, transparent, and elegantly ciliated bristles. These are the locomotive organs of the animal, whose total length, with the segments of the tail expanded, does not exceed seven to eight millimeters. The animal is found in running waters, at a depth of from half a meter to a meter and a half. It hides under stones of all sizes, and, as soon as it is touched, its first care is to fix itself by the breast to their rough surface, and then to swim off to a more quiet place. It fastens itself so firmly to the stone that it is necessary to pass a thin knife-blade under it in order to detach it.

Geoffroy, because of the two large eyes, and without paying attention to the ocelli, named this larva the "feather-tailed binocle." C. Dumeril, in 1876, found it again in pools that formed after rains, and named the creature (which is of a bluish color passing to red) the "pisciform binocle." Since then, this larva has been found in the Seine at Point-du-Jour, Bas-Meudon, and between Epone and Mantes. Latreille, in 1832, decided it to be a crustacean, and named it _Prosopistoma foliaceum_. In September, 1868, the animal was found at Toulouse by Dr. E. Joly in the nearly dry Garonne. Finally, in 1880, Mr. Vayssiere met with it in abundance in the Rhone, near Avignon.

The abnormal existence of a six-legged crustacean occupied the attention of naturalists considerably. In 1869, Messrs. N. and E. Joly demonstrated that the famous "feather-tailed binocle" was the larva of an insect. They found in its mouth the buccal pieces of the Neuroptera, and, under the carapax, five pairs of branchial tufts attached to the segments that are invisible outwardly. Inside the animal were found tracheæ, the digestic tube of an insect, and malpighian canals. Finally, in June, 1880, Mr. Vayssière was enabled to establish the fact definitely that the insect belonged among the Ephemerids. Two of the larvae that he raised in water became, from yellowish, gradually brown. Then they crawled up a stone partially out of water, the carapax gradually split, and the adults readily issued therefrom--the head first, then the legs, and finally the abdomen. At the same time, the wings, which were in three folds in the direction of their length, spread out in their definite form (Fig. 2). The insects finally flew away to alight at a distance from the water. The wings of the insect, which are of an iron gray, are covered with a down of fine hairs. The posterior ones soon disappear.

Perhaps the subimago in this genus of Ephemerids, as in certain others, is the permanent aerial state of the female.--_La Nature_.

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Connecticut is rapidly advancing in the cultivation of oysters. About 90,000 acres are now planted, and thirty steamers and many sailing vessels are engaged in the trade.

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THE COLOR OF WATER.

It is well known that the water of different lakes and rivers differs in color. The Mediterranean Sea is indigo blue, the ocean sky blue, Lake Geneva is azure, while the Lake of the Four Forest Cantons and Lake Constance, in Switzerland, as well as the river Rhine, are chrome green, and Kloenthaler Lake is grass green.

Tyndall thought that the blue color of water had a similar cause as the blue color of the air, being blue by reflected light and red by transmitted light. W. Spring has recently communicated to the Belgian Academy the results of his investigations upon the color of water. He proved that perfectly pure water in a tube 10 meters long had a distinctly blue color, while it ought, according to Tyndall, to look red. Spring also showed that water in which carbonate of lime, silica, clay, and salts were suspended in a fine state of division offered a resistance to the passage of light that was not inconsiderable. Since the red and violet light of the spectrum are much more feeble than the yellow, the former will be completely absorbed, while the latter passes through, producing, with the blue of the water itself, different shades of green.

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There is to be held in Paris this year, from the 1st to the 22d of July, an insect exhibition, organized by the Central Society of Agriculture and Insectology. It will include (1) useful insects; (2) their products, raw, and in the first transformations; (3) apparatus and instruments used in the preparation of these products; (4) injurious insects and the various processes for destroying them; (5) everything relating to insectology.

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A catalogue, containing brief notices of many important scientific papers heretofore published in the SUPPLEMENT, may be had gratis at this office.

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