Dolomite.—This mineral has been very common in this locality. It differs, perhaps, as I have before explained, from magnesite in containing lime besides magnesia, and from calc spar by the vice versa. Much of the magnesite in this serpentine contains more or less lime, and is consequently in places almost pure dolomite, although crystals are seldom to be found in this outcrop, it all occurring as veins about a half-inch thick and resembling somewhat the gurhofite of Staten Island, only that it is softer and less homogeneous in appearance. Its color is slightly tinged green, and specimens of it are not peculiarly unique, but perhaps worth removing. Its characteristics are: first, its burning to quicklime before the blowpipe, distinguishing it from pure magnesite; second, its slow effervescence in acids. Besides these, its specific gravity is 2.8, hardness, 8.5; from calcspar it cannot be distinguished except by chemical analysis, as the two species blend almost completely with every intermediate stage of composition into either calc spar, or, what occurs in this locality, aragonite, similar in composition to it, or dolomite. The color of the last, however, is generally darker, and it cleaves less readily into its crystalline form, which is similar to calc spar, and of which it is harder, 3.5 to 3 of calc spar.

Aragonite.—This mineral, identical in composition with calc spar, but whose crystalline form is entirely different, occurs in this locality in veins hardly recognizable from the magnesite or dolomite, and running into dolomite. It is not abundant, and the veins are limited in extent; the only distinguishment it has from the dolomite, practically, is its fibrous structure, the fibers being brittle and very coarse. If examined with a powerful glass, they will be seen to be made up of modified long prisms. The specific gravity is over 2.9, hardness about 4, unless much weathered, when it becomes apparently less. There are some small veins at the north end of the walk, and in them excellent forms may be found by cutting into the veins.

Brucite.—This mineral occurs here in fair abundance, it being one of the principal localities for it in the United States, and where formerly extremely unique specimens were to be obtained. It has been pretty well exhausted, however, and the fine specimens are only to be obtained by digging into the veins of it in the rock, which are quite abundant on the south end of the walk, and, as I before noted, as deep as possible from the top of the veins, as it is a closely packed mineral not occurring in geodes, druses, etc. Two forms of it occur; the one, nemalite, is in fibers of a white to brown color resembling asbestos, but the fibers are brittle, and hardly as fine as a typical asbestos. It is packed in masses resembling the brucite, from which it only differs in breaking into fibers instead of plates, as I have explained in my description of that species (see Part II). They are both readily soluble in acids, with effervescence, and infusible but crumble to powder before the blowpipe, or at least become brittle; when rubbed in mass with a piece of iron, they phosphoresce with a yellow light; specific gravity, 2.4, hardness, 1.5 to 2. Its ready solubility in acids without effervescence at once distinguishes it from any mineral that it may resemble. The specimens of nemalite may be more readily obtained than the brucite but fine specimens of both may be obtained after finding a vein of it, by cutting away the rock, which is not hard to do, as it is in layers and masses packed together, and which maybe wedged out in large masses at a time with the cold chisel and hammer, perhaps at the rate of three or four cubic feet an hour for the first hour, and in rapidly decreasing rate as progress is made toward the unweathered rock and untouched brucite, etc.

Serpentine.—Fair specimens of this may be obtained of a dark oil green color, but not translucent or peculiarly perfect forms. The variety known as marmolite, which splits into thin leaves, is plentiful and often well worth removing.

Chromic Iron.—Crystals of this are included in the denser rock in great abundance; they are very small, seldom over a few lines in diameter, of an iron black color, of a regular octahedral form; sometimes large crystals may be found in place or in the disintegrated loose rock. I have seen them a half inch in diameter, and a half dozen in a small mass, thus forming an excellent cabinet specimen. By finding out by observation where they are the thickest in the rock, and cutting in at this point, more or less fine crystals may be obtained. This is readily found where they are so very abundant, near the equidistant points of the walk, that no difficulty should be encountered in so doing. These characteristics are interesting, and if large specimens cannot be obtained, any quantity of the small crystals may be split out, and, as a group, used for a representative at least. Before the blowpipe it is infusible, but if powdered, it slowly dissolves in the molten borax bead and yields a beautiful green globule. The specific gravity, which is generally unattainable, is about 4.5, and hardness 5 to 6. Its powder or small fragments are attracted by the magnet. A few small veins of this mineral are also to be found horizontally in the rock, and small masses may be obtained. They are very rare, however. I have seen numerous agates from this locality, but have not found them there myself. They may be looked for in the loose earth over the outcrop, or along the wall of the river. Our next locality is Paterson, N. J., or rather in a trip first to West Paterson by the D.L. & W. Railroad, Boonton branch, then back to Paterson proper, which is but a short distance, and then home by the Erie road, or, if an excursion ticket has been bought, on the D.L. & W, back from West Paterson. Garret Rock holds the minerals of Paterson, and although they are few in number, are very unique. The first is phrenite. This beautiful mineral occurs in geodes, or veins of them, near the surface of the basalt, which is the characteristic formation here, and lies on the red sandstone.

These veins are but two or three feet from the surface, and the ones from which the fine specimens are to be and have been obtained are exposed by the railroad cutting about a thousand feet north of the station at West Paterson, and on the west side of the rails. Near or below the beds is a small pile of debris, prominent by being the only one in the vicinity near the rails. In this loose rock and the veins which are by this description readily found and identified, they are about three inches in thickness, and in some places widen out into pockets even a foot in diameter They look like seams of a dark earth, with blotches of white or green matter where they are weathered, but are fresher in appearance inside. The rock, in the immediate vicinity of the veins, is soft, and may be readily broken out with the hammer of, if possible, a pick bar, and thus some of these geode cavities broken into, and much finer specimens obtained than in the vein proper. Considerable occurs scattered about in the before-mentioned pile of loose rock and debris, and if one does not prize it sufficiently to cut into the rock, taking the chances of lucky find, plenty may be obtained thus; but as it has been pretty thoroughly picked over where loose, it is much more satisfactory to obtain the fine specimens in place in the rock. When the bed for the railroad was being cut here, many fine specimens were obtained by those in the vicinity, and the natives of the place have it in abundance, and it may be obtained from many of them for a trifle, if one is not inclined to work it out. The mineral itself occurs in masses in the vein of a white, greenish white, or more or less dark green color. Sometimes yellowish crystals of it occur plentifully in short thick prisms, but the common form is that of round coralloid bunches, having a radiated structure within. Sometimes it is in masses made up of a structure resembling the leaves of a book slightly opened, and in nearly every shape and size. Crystals of the various forms may be well secured, and also the different colors from the deep green to the blue white, always remembering that true, perfect crystals are of more value than masses or attempted forms. The specific gravity is 2.8 to 2.9, hardness nearly 7 before the blowpipe; it readily fuses after intumescing; it dissolves in hot acid without gelatinizing, leaving a flaky residue.

Datholite.—This mineral is very abundant as inferior specimens, and frequently very fine ones may be obtained. They occur all around Garret Rock at the juncture of the basalt and red sandstone, in pockets, and as heavy druses. They are most abundant near the rock cuttings between West Paterson and Paterson, and may be cut out by patient labor. This is a long known and somewhat noted locality for datholite, and no difficulty need be experienced in obtaining plenty of fair specimens. Near them is the red sandstone, lying under the basalt, and baked to a scoriaceous cinder. Upon this is a layer of datholite in the form of a crystalline plate, and over or above this, either in the basalt or hanging down into cavities in the sandstone, are the crystals or geodes of datholite. Old spots are generally exhausted, and consequently every new comer has to hunt up new pockets, but as this is readily done, I will not expend further comment on the matter. The datholite, as in other localities, consists of groups of small colorless crystals. Hardness, about 5; specific gravity, 3. Before the blowpipe it intumesces and melts to a glassy globule coloring the flame green, and forms a jelly when boiled with the acids.

Pectolite—This mineral is also quite abundant in places, the greater part occurring with or near the phrenite before mentioned, in small masses generally more or less weathered, but in very fair specimens, which are about an inch in thickness. It is readily recognized by its peculiar appearance, which, I may again repeat, is in fibrous masses, these fibers being set together in radiated forms, and are quite tough and flexible, of a white color, and readily fused to a globule before the blowpipe.

Feldspar.—This mineral occurs strewn over the hill from place to place, and is peculiarly characterized by its lively flesh red color, quite different from the dull yellowish gray of that from Staten Island or Bergen Hill. Fine crystals of it are rather rare, but beautiful specimens of broken groups may be obtained in loose debris around the hill and in its center. I have not been able to locate the vein or veins from which it has come, but persistent search will probably reveal it, or it may be stumbled upon by accident. Some of the residents of the vicinity have some fine specimens, and it is possible that they can direct to a plentiful locality. However, some specimens are well worth a thorough search, and possess considerable value as mineralogieal specimens. The specific gravity of the mineral is 2.6, and it has a hardness of 6 before the blowpipe. It is with difficulty fused to a globule, more or less transparent. It occurs undoubtedly in veins in the basalt and near the surface of the outcrop As this locality has never before been mentioned as affording this species, it is fresh to the amateur and other mineralogists, and there need be no difficulty in obtaining some fine specimens. Its brilliant color distinguishes it from other minerals of the locality.

It is possible that some of the other zeolites as mentioned under Bergen Hill occur here, but I have not been able to find them. The reason may be that the rock is but little cut into, and consequently no new unaltered veins are exposed.

COPPER MINES, ARLINGTON, N. J.—A short distance north of this station, on the New York and Greenwood Lake Railroad, and about nine miles from Jersey City, is one of the cuttings into the deposits of copper which permeate many portions of the red sandstone of this and the allied districts in Connecticut and Massachusetts, and which have been so extensively worked further south at Somerville and New Brunswick, etc. There are quite a variety of copper minerals occurring in these mines, and as they differ but little in anything but abundance, I will describe this, the one nearest to New York City, as I promised in commencing these papers. The locality of this mine may be readily found, as it is near the old turnpike from Jersey City, along which the water-pipes or aqueduct, are laid. By taking the road directly opposite to the station at Arlington, walking north to its end, which is a short distance, then turning to the left along the road, there crossing and turning north up the next road joining this, until the turnpike is reached; this is then followed east for about a quarter-mile, passing occasional heaps in the road of green earth, until the head of a descent is reached, when we turn off into the field to the left, and there find the mine near the heaps of greenish rocks and ore scattered about, a distance from the station of about a mile and a half through a pleasing country. The entrance to the mine is to the right of the bank of white earth on the edge of, and in the east side of the hill; it is a tunnel more or less caved in, running in under the heaps of rock for some distance. It will not be necessary, even if it were safe, to venture into the mine, but all the specimens mentioned below may be obtained from the heaps of ore and rock outside, and in the outcrops in the east side of the hill, a little north of the mouth of the tunnel to the mine. The hammer and cold chisel will be necessary, and about three hours should be allowed to stay, taking the noon train from New York there, and the 5.09 P.M. train in return, or the 6.30 A.M. train from the city, and the 1.57 P.M. in return. This will give ample opportunity for the selection of specimens, and, if time is left, to visit the water works, etc.

Green Malachite.—This is the prominent mineral of the locality, and is conspicuous by its rich green color on all the rocks and in the outcrops. Fine specimens of it form excellent cabinet specimens. It should be in masses of good size, with a silky, divergent, fibrous structure, quite hard, and of a pure oil green color, for this purpose. Drused crystals of it are also very beautiful and abundant, but very minute. As the greater part of it is but a sixteenth or eighth of an inch in thickness, it may require some searching to secure large masses a quarter to a half-inch in thickness, but there was considerable, both in the rock, debris, and outcrop, remaining the last visit I made to the place a few months ago. The mineral is so characterized by its color and solubility in acid that a detailed description of it is unnecessary to serve to distinguish it. Its specific gravity is 4, and hardness about 4. It decrepitates before the blowpipe, but when fused with some borax in a small hollow on a piece of wood charcoal, gives a globule of copper. It readily dissolves in acids, with effervescence, as it is a carbonate of copper.

Red Oxide of Copper—This rather rare mineral is found in small quantities in this mine, or near it, in the debris or outcrop. Perfect crystals, which are of a dodecahedral or octahedral form, are fairly abundant. They are difficult to distinguish, as they are generally coated, or soiled at least, with malachite. The color proper is of a brownish red, and the hardness about 4, although sometimes, it is earthy, with an apparent hardness not over 2. The crystals are generally about a quarter of an inch to a half of an inch in diameter, and found inside the masses of malachite. When these are broken open, the red copper oxide is readily distinguished, and may be separated or brought into relief by carefully trimming away the malachite surrounding it as its gravity (6) is much greater than malachite. When a piece of the last is found which has a high gravity, it may be suspected and broken into, as this species is much more valuable and rarer than the malachite which is so abundant. It dissolves in acids like malachite, but without effervescence, if it be freed from that mineral, and acts the same before the blowpipe. Sometimes it may be found as an earthy substance, but is difficult to distinguish from the red sandstone accompanyit, which both varieties resemble, but which, not being soluble in the acids, find having the blowpipe reactions, is thus characterized. This red oxide of copper does not form a particularly showy cabinet specimen, but its rarity and value fully compensate for a search after it. I have found considerable of it here, and seen some little of it in place remaining.

Chrysorolla.—This mineral, very abundant in this locality, resembles malachite, but has a much bluer, lighter color, without the fibrous structure so often present in malachite, and seldom in masses, it only occurring as light druses and incrustations, some of which are very beautiful, and make very fine cabinet specimens. Its hardness is less than that of the other species, being under 3, and a specific gravity of only 2, but as it frequently occurs mixed with them, is difficult to distinguish. It does not dissolve in nitric acid, although that takes the characteristic green color of a solution of nitrate of copper, as from malachite or red oxide. This species is found all over this locality, and a fine drused mass of it will form an excellent memento of the trip.

Copper Glance.—This mineral is quite abundant in places here, but fine crystals, even small, as it all is, are rare. That which I have seen has been embedded in the loose rock above the mine, about a quarter inch in diameter, and more or less disguised by a green coating of chrysocolla. The color of the mineral itself is a glistening grayish lead color, resembling chromite somewhat in appearance, but the crystals of an entirely different shape, being highly modified or indistinct rhombic prisms. The specific gravity is over 5, and the hardness 4. Before the blowpipe on a piece of wood charcoal it gives off fumes of sulphur, fuses, boils, and finally leaves a globule of copper. In nitric acid it dissolves, but the sulphur in combination with it separates as a white powder. A steel knife blade placed in this solution receives a coating of copper known by its red color.

Erubescite—This mineral occurs massive in the rock here with the other copper minerals, and is of a yellowish red color, more or less tarnished to a light brown on its surface, Before the blowpipe on charcoal it fuses, burns, and affords a globule of copper and iron, which is attracted by the magnet. Its specific gravity is 5, hardness 3. It resembles somewhat the red oxide, but the low gravity, inferior hardness, lighter color, and blowpipe reaction distinguish it. These are the only copper minerals likely to be found at this mine, and the following table and note will show their characteristics:

Name. Speci- Hardness Action of Action of Color. Form. fic Blowpipe Heat. Hot Nitric Gravity. Acid.

Mala- From 4 From 3 Decrepitates, Dissolves Pure Oil Fibrous, chite to 4.5 to 4 but fuses with with Green. massive, borax to a effer- or in- green bead. vescence crusting.

Red 6 From 3.5 On charcoal Dissolves A deep Modified Oxide to 4 yields a without brownish crystals. globule of effer- red. copper. vescence

Chryso- From 2 From 2 Infusible. Partly Bright Incrus- colla to 2.3 to 3 soluble bluish tations. green.

Copper 5 From 2.5 Fumes of Copper Grayish Modified Glance to 3 sulphur and a soluble, Lead. rhombic globule of sulphur prisms. copper deposits

Erube- 5 From 3 Fumes of Partly Yellowish Massive. scite to 3.5 sulphur and soluble red or magnetic tarnished. globule.

Malachite is characterized by its color from Copper Glance and Red Oxide and Erubescite, and from Chrysocolla by the action of the acid, the fibrous structure and blowpipe reaction, gravity, and hardness.

Red Oxide is distinguished from Erubescite, which it alone resembles, by its darker color, higher specific gravity, and yielding a globule of pure copper.

Chrysocolla is characterized by its low specific gravity, light color, lack of fibrous structure, blowpipe reactions, and the acid.

Copper Glance is distinguished by its color, fumes of sulphur, and globule of copper.

Erubescite is distinguished from Red Oxide, which it alone resembles, by its lighter color, great solubility when pure, and yielding a magnetic globule before the blowpipe in the hollow of a piece of wood charcoal, which is used instead of platinum wire in this investigation.

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ENTOMOLOGY.

[Footnote: From the American Naturalist, November, 1882.]

THE BUCKEYE LEAF STEM BORER.—In our account of the proceedings of the entomological sub-section of the A.A.A.S., at the 1881 meeting (see American Naturalist, 1881, p. 1009), we gave a short abstract of Mr. E.W. Claypole's paper on the above insect, accepting the determination of the species as Sericoris instrutana, and mentioning the fact that the work of Proteoteras aesculana Riley upon maple and buckeye was very similar. A letter recently received from Mr. Claypole, prior to sending his article to press, and some specimens which be had kindly submitted to us, permit of some corrections and definite statements. We have a single specimen in our collection, bred from a larva found feeding, in 1873, on the blossoms of buckeye, and identical with Mr. Claypole's specimens, which are in too poor condition for description or positive determination. With this material and with Mr Claypole's observations and our own notes, the following facts are established:

1st. We have Proteoteras aesculana boring in the terminal green twigs of both maple and buckeye, in Missouri, and often producing a swelling or pseudo-gall. Exceptionally it works in the leaf-stalk. It also feeds on the samara of maple, as we reared the moth in June, 1881, from larvae infesting these winged seeds that had been collected by Mr. A.J. Wethersby, of Cincinnati, O.

2d. We have an allied species, boring in the leaf-stalk of buckeye, in Ohio, as observed by Mr. Claypole. It bears some resemblance to Proteoteras aesculana, but differs from it in the following particulars, so far as can be ascertained from the poor material examined: The primaries are shorter and more acuminate at apex. Their general color is paler, with the dark markings less distinctly separated. No distinct tufts of scales or knobs appear, and the ocellated region is traversed by four or five dark longitudinal lines. It would be difficult to distinguish it from a rubbed and faded specimen of aesculana, were it not for the form of the wing, on which, however, one dare not count too confidently. It probably belongs to the same genus, and we would propose for it the name of claypoleana. The larva is distinguished from that of aesculana by having the minute granulations of the skin smooth, whereas in the latter each granule has a minute sharp point.

3d. Sericoris instrutana is a totally different insect. Hence our previous remarks as to the diversity of food-habit in this species have no force—C.V.R.

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DEFOLIATION OF OAK TREES BY DRYOCAMPA SENATORIA IN PERRY COUNTY, PA.—During the present autumn the woods and road-sides in this neighborhood (New Bloomfield) present a singular appearance in consequence of the ravages of the black and yellow larva of the above species. It is more abundant, so I am informed, than it has ever been before. In some places hardly any trees of the two species to which its attack is here limited have escaped. These are the black or yellow oak (Q. tinctoria) with its variety (coccinea), the scarlet oak and, the scrub oak (Q. ilicifolia). These trees appear brown on the hill-sides from a distance, in consequence of being altogether stripped of their leaves. The sound of the falling frass from the thousands of caterpillars resembles a shower of rain. They crawl in thousands over the ground, ten or twelve being sometimes seen on a square yard. The springs and pools are crowded with drowned specimens. They are equally abundant in all parts of the county which I have visited during the past week or two—the central and southeastern.—E. W. Olaypole, New Bloomfield, Pa.

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EFFICACY OF CHALCID EGG-PARASITES.—Egg-parasites are among the most efficient destroyers of insects injurious to vegetation, since they kill their victim before it has begun to do any damage; but few persons are aware of the vast numbers in which these tiny parasites occasionally appear. Owing to the abundance of one of them (Trichogramma pretiosa Riley), we have known the last brood of the cotton-worm to be annihilated, and Mr. H.G. Hubbard reported the same experience at Centerville, Fla. Miss Mary E. Murtfeldt has recently communicated to us a similar experience with a species of the Proctotrupid genus Telenomus, infesting the eggs of the notorious squash-bug (Coreus tristis). She writes: "The eggs of the Coreus have been very abundant on our squash and melon vines, but fully ninety per cent. of them thus far [August 2] have been parasitized—the only thing that has saved the plants from utter destruction."

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ON THE BIOLOGY OF GONATOPUS PILOSUS Thoms—Professor Josef Mik, in the September number of the Wiener Entomologische Zeitung (pp. 215-221, pl. iii), gives a most interesting account of the life history of the curious Proctotrupid, Gonatopus pilosus Thoms., which has not before been thoroughly understood. Ferris, in his "Nouvelles excursions dans les grandes Landes," tells how, from cocoons of parasitic larvae on Athysanus maritima (a Cicadellid) he bred Gonatopus pedestris, but this he considered a secondary parasite, from the fact that it issued from an inner cocoon. It appears from the observations of Mik, however, that it was in all probability a primary parasite, as with the species studied by the latter (G. pilosus) the larva spins both an outer and an inner cocoon. The larva of Gonatopus pilosus is an external parasite upon the Cicadellid Deltocephalus xanthoneurus Fieb. The eggs are laid in June or July, and the larvae, attaching themselves at the junction of two abdominal segments, feed upon the juices of their host. But one parasite is found upon a single Cicadellid, and it occasionally shifts its position from one part of the abdomen to another. Leaving its host in September, it spins a delicate double cocoon in which it remains all winter in the larva state, transforming to pupa in May, and issuing as an imago in June.

It will be remembered that the female in the genus Gonatopus is furnished with a very remarkable modification of the claws of the front tarsi, which are very strongly developed, and differ somewhat in shape in the different species. It has usually been supposed that these claws were for the purpose of grasping prey, but Professor Mik offers the more satisfactory explanation that they are for the purpose of grasping the Cicadellids, and holding them during the act of oviposition.

It is interesting to note that there is in the collection of the Department of Agriculture a specimen of Amphiscepa bivittata Say, which bears, in the position described above, a parasitic larva similar to that described by Mik. It left its victim and spun a white cocoon, but we failed to rear the imago. It is probably the larva of a Gonatopus, and possibly that of the only described American species of the genus, Gonatopus contortulus Patton (Can. Ent., xi p. 64).

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SPECIES OF OTIORHYNCHIDAE INJURIOUS TO CULTIVATED PLANTS—Of our numerous species of this family, we know the development and earlier stages of only one species, viz, Fuller's rosebeetle (Aramigus Fulleri[1]). A few other species have attracted attention by the injury caused by them as perfect insects. They are as follows: Epicoerus imbricatus, a very general feeder; Pachnoeus opalus and Artipus floridanus, both injurious to the orange tree. Of a few other species we know the food-plants: thus Neoptochus adspersus feeds on oak; Pachnoeus distans on oak and pine; Brachystylus acutus is only found on persimmon; Aphrastus toeniatus lives on pawpaw (but not exclusively); Eudiagogus pulcher and rosenschoeldi defoliate the coffee-weeds (Cassia occidentalis and other species of the same genus). Two very common species, Pandeleteius hilaris and Tanymecus confertus, appear to be polyphagous, without preference for any particular plant. Very recently the habits of another species, Anametis grisea Horn, were brought to our knowledge by Mr. George P. Peffer, of Pewaukee, Wis., who sent us specimens of the beetle accompanied by the following communication: "The larger curculio I send you is working around the roots of apple and pear trees, near the surface of the ground or around the union where grafts are set. I found fifteen of the larvae on a small tree one and a half inches in diameter. The beetle seems to lay its eggs just where the bark commences to be soft, near or partly under the ground. The larvae eat the bark only, but they are so numerous as to girdle the tree entirely in a short time."—C. V. Riley.

[Footnote 1: Vide Annual Report Department of Agriculture, 1878, p. 257.]

BOMBYLIID LARVAE DESTROYING LOCUST EGGS IN ASIA MINOR.—The eggs of locusts in Cyprus and the Dardanelles, as we learn from the Proceedings of the London Entomological Society, are much infested with the parasitic larvae of Bombyltidae, though these were previously not known to occur on the island. This fact shows that the habit which we discovered among some of our N. A. Bombyliids recurs in other parts of the world, and we have little doubt that careful search among locust eggs will also reveal the larval habits of some of the Meloidae in Europe and elsewhere. Indeed, notwithstanding the closest experiments of Jules Lichtenstein, which show that the larva of the Spanish blister-beetle of commerce will feed on honey, we imagine that its more natural food will be found in future to be locust eggs. The particular Bombyliid observed by Mr. Frank Calvert destroying locusts in the Dardanelles is Callostoma fascipennis Macq., and its larva and pupa very closely resemble those of Triodites mus. which we have studied and figured (see Vol. XV., pl. vi.). We quote some of Mr. Calvert's observations:

"On the 24th of April I examined the larvae in the ground; the only change was a semi-transparent appearance which allowed of a movable black spot to be seen in the body. On the 8th June about fifty per cent. of the larvae had cast a skin and assumed the pupal state in their little cells: the color yellowish-brown, darkening to gray in the more advanced insect. About one per cent. of the cells, in which were two skins and an aperture to the surface, showed the perfect insect to have already come out of them. A gray pupa I was holding in my hand suddenly burst its envelope, and in halt a minute on its legs stood a fly, thus identifying the perfect insect.... I found the fly, now identified, sucking the nectar of flowers, especially of the pink scabious and thistle, plants common in the Troad. (Later on I counted as many as sixteen flies on a thistle-head.) The number of flies rapidly increased daily until the 13th, when the ground appeared pitted all over with small holes from whence the parasite had issued. A few pupae were then still to be found—a larva the rare exception. The pupal state thus seems to be of short duration. It was very interesting to watch the flies appearing above ground; first the head was pushed out; then, with repeated efforts, the body followed; the whole operation was over in two or three minutes; the wings were expanded, but the colors did not brighten until some time after. Occasionally a pupa could not cast off its envelope, and came wriggling out of the ground, when it was immediately captured by ants. Unfortunate flies that could not detach the covering membrane adhering to the abdomen, also fell a prey, as indeed many of the flies that could not get on their legs in time. The flies for the first time 13th June, were seen to pair, but this rarely."

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SPARROWS IN THE UNITED STATES.—EFFECT OF ACCLIMATION, ETC.

The house sparrows were first brought to New York city in 1862. They might have been introduced in consideration of the scientific usefulness of the experiment; but the importation was made solely in view of the benefit to result from their immense consumption of larvae.

I have long observed peculiarities in their acclimation which are hardly known at all, and which must have a scientific importance. The subject might also be worthy of general interest, so numerous and familiar have the sparrows become all over our country.

Walking on Fifth avenue, or in the parks of the city, during the breeding season, one's attention is repeatedly attracted by the pitiful shrill call of a sparrow fallen on the pavement upon its first attempt at flight, or by the stronger note of a mother sparrow, sharply bewailing the fate of a little one, killed by the fall, or dispatched alive by the cat.

Should we take and examine these little weaklings, we should find generally that they are at a period when they normally should have the strength for flight, and we should also find that they are almost always of a lightish tint, some with head white, others with streaks and spots of white on the tail or back, and occasionally one is found entirely white, with red eyes—a complete albino. It is an accepted fact that the city-sparrow is everywhere of a lighter color than that of the country. But here the greater lightness exists in so many cases, to such a degree, and particularly in female sparrows, that it should be discussed, at least in part, under the head of albinism.

That so many which lack the muscular strength in their wings should be so generally affected with albinism, is a significant fact to those interested in this phenomenon.

Many hold, with Darwin, that this extraordinary want of coloring matter, occasionally met with in all animals, is not to be regarded as an index denoting an unhealthful condition of the animal. That it is so often united in the young sparrow with physical inability, argues favorably for those who bold a different view.

In my observations, what has struck me as a most curious fact, and what I have found to be generally ignored, is that this wide-spread albinism and general weakness of our acclimated house-sparrow are not found among its progenitors.

Throughout several sojourns that I made in Europe. I searched for a token of the remarkable characteristics existing here, but I never succeeded in finding one in England, France, or in Germany, nor have I met an observer that has.

This albinism and weakness, existing simultaneously to such an extent in our young house-sparrows, are evidently the result of their acclimation.

The hypothesis that our now numerous sparrows, being descended from a few European birds, and that, probably, continual and close reproduction among individuals of the same stock, as in the case of our original few sparrows, has encouraged weakness in the race, can hardly serve as an explanation of this phenomenon, because the sparrow is so prolific that, after a few years, so many families had been formed that the relation between them became very distant.

The reason for the greater proportion of albinism found in the young is obvious; the young sparrows affected with albinism, lacking usually the physical strength to battle their way in life, meet death prematurely, and thus a very small proportion of the number is permitted to reach maturity, while those that do owe it to some favoring circumstance. Many are picked up and cared for by the public; and among those to whom these sparrows generally owe such prolongation of life are the policemen in our public parks, who often bring these little waifs to their homes, keeping some, and sending others out into the world, after caring for them until they have acquired the sufficient strength. However, almost all of these albino-sparrows are picked up by the cat, and immediately disposed of to the feline's physical benefit. They form such a prominent diet among the cats near Washington Park, where I live, that, upon the removal of some of our neighbors to the upper part of the city, it was noticed that their cat became dissatisfied and lean, as sparrow-meat is not to be found so extensively there, but it finally became resigned, finding it possible to procure about three sparrows daily.

And here attention should be called to the method employed by our cats to catch not only the weak, but fine, healthy sparrows as well; it ought perhaps to be looked upon as a mark of intellectual improvement, for originally their attempts consisted chiefly in a very unsuccessful giving chase to the flying bird, whereas the cats of to-day are skilled in a hundred adroit devices. It has often been a source of enjoyment to watch their well-laid schemes and delicate maneuverings.

What wonder then, with such dainty fare at his disposal, that the cat is often found to have become indifferent to rats, and even to mice?

There are several notable changes, no more desirable than the foregoing, which have been caused by the introduction of the house-sparrow. The only positive benefit which occurs to me is that the measuring worm, which formerly infested all our vegetation, is now very nearly extinct through the instrumentality of the sparrows. A pair of these, during the breeding-season, destroys four thousand larvae weekly.

In some places, complaints are made that their untidy nests mar the appearance of trees and walls.

The amount of havoc in our wheatfields created yearly by them is enormous. Their forwardness and activity have driven all other birds from where they have settled, so that the hairy caterpillars, which sparrows do not eat and which used to be extensively consumed by other birds, are now greatly on the increase, probably the only creatures, at present, enjoying the domestication of the sparrow in this country.... I have also to remark that the sparrows here betray much less pugnacity than in Europe.—E.M., M.D.

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It is stated in the Chemical Review that recent analyses of the water from the Holy Well at Mecca, which is so eagerly drunk by pilgrims, show this water to be sewage, about ten times stronger than average London sewage.

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HOW TO ESTABLISH A TRUE MERIDIAN.

In looking over the excellent article of Professor S. M. Haupt, in the SCIENTIFIC AMERICAN SUPPLEMENT, No. 360, on the subject of finding the meridian, I discovered that one important step is not given, which, might prove an embarrassment to a new beginner.

In the fourth paragraph, in the third column of page 5,748, he says: "Having now found the altitude, correct it for refraction, ... and the result will be the latitude."

It will be observed that this result is only the true altitude of the star. The latitude is found by further increasing or diminishing this altitude by the polar distance of the star.

This paper will be of great value to engineers and surveyors, for the elementary works on surveying have not treated the subject clearly.

H. C. PEARSONS, C.E.

Ferrysburg, Mich.

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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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