that only one slide in twenty, perhaps one scale in five thousand, was of any use. In his slide prepared by Mr. R. Beck there are only two well marked scales, which appear to be the exception and not the rule. Dr. Josiah Curtis, of Knoxville, Tenn., has been successful in collecting species of Lepisma, "Podura," etc.

THE STUDY OF "DIFFICULT" DIATOMS.-Mr. J. Edwards Smith of Ashtabula, Ohio, writes the following note which is suggestive of the experience of many microscopists who study the finer diatoms without making a specialty of them.

"I find that Pritchard describes Navicula cuspidata as having close transverse striæ. I have slides of this diatom, mounted dry and in balsam, and with my Tolles' dry, or wet, have no difficulty in showing longitudinal striæ, far finer than the transverse ; indeed when mounted dry both sets can be plainly seen at once. Is there anything remarkable about this?

I notice that Möller places Navicula crassenervis as the 18th on his 'Probe Platte'. I fail to discover striæ on this diatom either in balsam or mounted dry. Pritchard says they are sometimes wanting. The objectives above named show the fine lines in No. 17 (Cymatopleur ælliptica) very nicely, but fail on Nos. 18, 19 and 20. Our friends here are interested to know what others are doing with this Probe Platte.' Has Amphipleura pellucida been resolved in balsam? When, by whom, and with what lenses?"

6

ANS.-Nothing can be more certain than the uncertainty of what has been known, in regard to the markings and structure of diatoms. It would be rash at present to pronounce any shell free from markings, and would probably be repeating a mistake too often made already. Different shells of the same species vary greatly in "difficulty," but no explanation or excuse is necessary for a dry failing to go entirely through the series on the testplate. It is by no means easy, though sometimes possible, to resolve A. pellucida in balsam with dry lenses and ordinary illumination. With immersion lenses, however, and monochromatic illumination, there is no difficulty in accomplishing this with objectives of Tolles, Wales, Powell and Lealand, Beck, Hartnack, and Nachet, and doubtless several other makers. About two years ago Count F. Castracane resolved and photographed A. pellucida in balsam, with French lenses and monochromatic sunlight. For a method by which this can be easily accomplished see Dr. Woodward's paper in the NATURALIST for April last.

NOTES.

AGAIN has science been called upon to give up one of her brightest lights and most enthusiastic devotees, and many of our readers have in the death of Dr. WILLIAM STIMPSON to mourn for a dear friend. Dr. Stimpson was born in Cambridge, Mass., and early became devoted to Natural History pursuits. He also had the good fortune of being under the guidance of Agassiz and soon became an original investigator and distinguished as a malacologist. His first publication was on the marine shells of New England, in 1851. From this time he pursued the study of Marine Zoology with the greatest vigor, and dredged and collected along our Atlantic Coast from Florida to Grand Menan, until he became the authority in the lower forms of animal life, especially in the classes of Crustacea, and Mollusca, and until Mr. Verrill commenced his work on our Radiates, Dr. Stimpson was the acknowledged authority in that group also. In the classes of Mollusca and Crustacea of our Atlantic coast, Dr. Stimpson was to the time of his death the acknowledged head of the able band of workers in these departments, while his connection with the Government Exploring Expedition to the North Pacific, as naturalist, gave him a wide field of work in his most favorite study of the Crustacea, in which he shared equally with Dana the honors of the scientific world. As a dredger Dr. Stimpson early became noted, and taking his first lessons in our own harbor of Salem, under the guidance of Dr. Wheatland, he soon became the pioneer in this science along our whole coast, and his very last work was the superintendence of the deep sea dredging off the coast of Florida under the direction of the Coast Survey. Dr. Stimpson's connection with the Chicago Academy of Science, as the successor of the lamented Kennicott, is known to all, and to the disastrous fire, which in one short hour destroyed all his material, manuscripts, drawings, specimens and library, must we attribute the close of his life at the age of forty-two years. For though suffering from lung disease, there is little doubt but that for the fearful calamity which so suddenly destroyed all his work and hopes, he would have lived to have seen published the valuable works, which, owing to a fatal delay on the part of government, are now irrevocably gone;

though the many descriptions and preliminary papers which he published, and his early works, will forever connect his name with the marine zoology of the world.

THE Committee to arrange for the next meeting of the AsSOCIATION FOR THE ADVANCEMENT OF SCIENCE have informed us, just as we go to press, that the meeting will not be held in San Francisco as previously announced, but in Dubuque, beginning on Wednesday morning, August 21st, at 10 o'clock. We shall give all the details possible in our August number, and the circulars to members will undoubtedly now be issued at once by the Local Committee.

IT will be noticed that the Herbarium of the late Rev. M. A. CURTISS of Hillsboro, N. C., the veteran and highly esteemed Mycologist, is offered for sale in our advertising pages. But a few months ago we were in correspondence with Dr. Curtiss, relative to the publication of his manuscripts and drawings on the edible fungi of the United States, and though aware of his feeble health we had no reason to suppose his life labors were so nearly over; the first intimation we received being the request to publish the advertisement given in this number. Dr. Curtiss has so long been identified with the study of the important and interesting group of Fungi, and has so extensively exchanged and collected specimens, that his collection must be of the highest value as an authentic one in this most difficult department, and we trust that it will at once be secured for some prominent herbarium where his life-long labors will be appreciated and made useful.

"It is with very great regret that we have to record the death of Mr. GEORGE ROBERT GRAY, which took place on the 6th of May, after a short illness. He was born in the year 1808, at Little Chelsea, and was appointed an Assistant in the Zoological Department of the British Museum in 1831. At the time of his death, he occupied the post of Assistant Keeper of that department. He established his reputation as an ornithologist by his "Genera of Birds," a great work, in the production of which he was engaged for twelve years, from 1837 to 1849. From that time he was facile princeps in this branch of science, to which he devoted himself almost exclusively. Only a short time before his death he completed his invaluable "Handlist of Birds," published in three volumes by the Trustees of the British Museum.".

Academy.

THE Boston Society of Natural History have very wisely decided to offer the Annual Walker Prize for 1873 for a memoir "On the development and transformations of the Common House Fly," thus not only carrying out the liberal bequest of Dr. Walker, in offering pecuniary assistance to worthy investigators, but at the same time calling attention to how little is known of the early life-history of one of the most abundant of insect pests. Trusting that the prize may induce several of our entomologists to turn their attention, for this year at least, to the much neglected group of Diptera we refer to the advertisement for particulars.

ANSWERS TO CORRESPONDENTS.

E. M.-The Diatom of your figure and description may possibly be Triceratium spinosum B., which has been obtained from Florida, and which varies so greatly that it has been described under several different names. We should like to have speci mens for further examination. — R. H. W.

T. W.-The Society Screw," to which are fitted all American and a large proportion of European objectives, is practically indispensable to a satisfactory microscope at the present day; yet it should not be considered by any means indispensable in buying a microscope. It can be added, by means of an adapter costing about one dollar, to any microscope large enough to work the modern objectives. - R. H. W.

H. H. Y.-Wants to know what causes the bursting and curling of the pod of Touchme-not (Impatiens)? Strongly unequal tension: the outer and juicy part of the wall wants to expand, the inner to contract: a slight displacement, destroying the equil:brium of the pressure of the valves on each other, gives rise to the result. He also wants to know what force governs the sensitive plant"? The movement is a vital one-as much so as the movement of our hand in writing. But the force that moves the leafstalks is, again, one of tension, —unequal tension upon different sides. How the unequal tension is brought about, if to be explained at all, cannot be explained in a word

or two.

E. H., Jr. Amherst, Mass.-The capture of two specimens of the Cape May Warbler (Dendroca tigrina) in May of this year at Amherst, Mass., by Messrs. S. Dickinson and W. A. Stearns, Jr., is an interesting fact. It is properly regarded as a rare bird in this State, occurring sparingly and at irregular intervals. (See Amer. Nat., Vol. III. p. 578.)-J. A. A.

L. H. N.-(Finds Dr. Woodward's method of resolving Amphipleura pellucida to work splendidly.) Should you succeed in resolving the above diatom, in balsam, with any lenses of less than 1-8 in. equivalent focus, rated on the principle of 1 in. by 10, we should be glad to know the particulars, including the amplifying power and angu lar aperture of the objective both at open point and at the working point as used for the resolution. We should also be glad to know the amplifying power and working angle of your Powell and Lealand 1-16 as adjusted for the work so well done by it.-R. H. W. L. F. A., Wilton, Maine.- Some grasshoppers hibernate in the perfect, some in the larva or pupa, and others in the egg state. The borer which you find far up in the trunk of your apple trees, is doubtless Chrysobothris femorata Fabr., popularly known as the Flat-headed Borer.-C. V. R.

C. N. S., Fayetteville, Pa. - The small borers which infested your young peach shoots while they were in blossom, judging from your description, and from a dried and flattened specimen received through Mr. S. S. Rathvon of Lancaster, were the larvæ of a small slate-colored moth - Anartia lineatella Zeller. We have bred it from peach-stemboring larvæ, and it has similar habits in Europe, being common to both countries. The larva of Gortyna nitela Guen., a much larger moth, also bores into peach stems.C. V. R.

J. L. L. Jr., Boston, Mass.- Your figure represents the Book-Scorpion or False-Scorpion (Chelifer cancroides Linn.). It runs sidewise and backwards as well as forwards; feeds on mites and book-lice (Psoci) and is consequently not injurious. — C. V. R.

C. W., WETHERSFIELD, CONN.-The two worms which you send are both larvæ of the Imported Currant-worm (Nematus ventricosus Klug). The spotted specimen not having yet undergone its last molt, while the immaculate specimen has. One of the peculiarities of this larvæ being that it loses, after the last molt, the black spots which characterize it in the earlier stages. If Mr. Packard in his first Report has not given the systematic name, it is probably an oversight. The was named affinis and the trimaculatus by St. Fargeau, who, of course, knew nothing of the insect's habits; and Dr. Fitch, by a singular oversight, subsequently adopted St. Fargeau's name.C. V. R.

BOOKS RECEIVED.

Second Annual Report on the Noxious Insects of the State of Illinois. By William LeBaron. 8vo pamph. 1872. Springfield.

Annual Report of the Trustees of the Museum of Comparative Zoology at Harrard College, in Cambridge, together with the Report of the Director for 1871. 8vo pamph. Boston, 1872.

Fourth Annual Report on the Norious, Beneficial and other Insects of the State of Missouri. By Charles V. Riley Illustrated. Svo pamph. 1872. Jefferson City.

Bulletin of the Museum of Comparative Zoology. Vol. III. No.4. Preliminary notice of a few species of Echini. By Alexander Agassiz. Svo pamph. 1872.

Annual Report of the Board of Regents of the Smithsonian Institution for 1870. 8vo. pp. 494, Washington, 1871. [April, 1872.} Spectrum Analysis Explained and Spectrum Analysis Discoveries. Forming Nos, 3 and 4 of Half-hour recreations in Popular Science. Edited by Dana Estes. 12mo. Boston. Lee and Shepard, 1872.

Societe Malacologique de Belgique. (Bulletins des Seances. 8vo. pp. 25-40. 1872.

Second Annual Report on the Injurious and Beneficial Insects of Massachusetts made to the State Board of Agriculture. By A. S. Packard, Jr. 8vo. pamph. 1872. Boston.

Affinities of Paleozoic Tabulate Corals with existing Species. By A. E. Verrill. (From the Am, Jour, of Sci., and Arts. Vol. 3. March, 1872.)

Spiritualism answered by Science. By Edward W. Cox. Recent Additions to the Molluscan Fauna of New England. Jour, of Sci. and Art. Vol. III. March and April, 1872.) Progressive Bee Culture. Illustrated and Systematized. Cincinnati.

New York. Henry L. Hinton. 1872. By A. E. Verrill. (From the Am. 8vo pamph. New Haven.

By Dr. L. Adair. 8vo pamph. 1872.

Catalogue of the Birds of Kansas. Contributed to the Kansas Academy of Science. By Frank H. Snow. 8vo pamph. Topeka, Kansas. 1872.

Tidsskrift for Populære Fremstillinger af Naturvidenskaben. 8vo pamph. Fjerde Ræke: Fjerde Binds. Forste Hefte. Fjerde Binds andet Hefte. 1872. Kjobenhavn.

Observatorio Astronomico Arjentino. Discursos sobre su Inauguracion revificada el 24 de Octubre de 1871. 8vo pamph. 1872. Buenos Aires.

Hora Societatis Entomologica Rossicæ. 8vo. Tome vil. No. 4. Tome vill. No. 2. 1871. Petropoli.

La Production Animale et Vegetale. 8vo. 1867. Paris.

Bulletin Mensuel de la Societe d'Acclimation. 8vo. Tome vill. Nos.1-12. 1871. Paris. Bulletin de la Societe Imperiale des Naturalistes de Moscou. 8vo. Tome xliv. Nos. 1 et 2. 1871. Moscou.

Jahrbuch der kaiserlichen-koniglichen Geologischen Reichsanstalt. 8vo. Band xxi. Nos. 3 and 4. 1871. Wien.

Bulletins de l'Institut National Generois. 8vo. Vol. xvi. No. 35. 1870. Geneve.

Bulletin de la Societe des Sciences Naturelles de Neuchatel. 8vo. Tome xvi. 1871. Neuchatel. Pisciculture dans l'Amerique du Nord. (Extrait du Bulletin de la Societe d'Acclimation.) Svo pamph. 1871.

Archiv fur Anthropologie. 4to. Funfter Band. 1871. Braunschweig.

Annales Academici. 1866-1867. 4to. 1871. Leiden.

Proceedings of the Royal Society. 8vo. Vol. xviii. Nos. 119-122. 1870. Vol. xix. Nos. 123129. 1871. London.

Third and Fourth Annual Reports of the Flax Extension Association. 8vo pamphs. 1870, 1871. Belfast.

Instructions for the Culture and Preparation of Flax in Ireland. By Michael Andrews, Jr. 8vo pamph. 1870. Belfast.

The Physician's Annual for 1872. 12mo pamph. Philadelphia.

Lecture on Water, delivered before the American Institute of the City of New York. By C. F. Chandler. Svo pamph. 1871. Albany.

Instinct in Animals and Men, By P. A. Chadbourne. 12mo. Cloth. New York. G. P. Putnam & Son. 1872.

First Annual Report of the Board of Commissioners of the Department of Public Parks, for the year ending May 1, 1871. 8vo. Illustrated (City Document). New York.

Annual Address before the American Geographical Society in New York. 8vo pamph. By Daniel C. Gitman. 1872. New York.

Fourth Biennial Report of the Board of Trustees of the Iowa State Agricultural College and Farm, to the Governor of Iowa. Svo pamph. 1872. Des Moines.

Illustrated Catalogue of the Museum of Comparative Zoology, at Harvard College. No. iv. Deep Sea Corals by L F. de Pourtales. 93 pages. 8 plates. No. v. The Immature State of the Odonata. Part 1. Sub-family Gomphina by Louis Cabot; 17 pages. 3 plates. No, vi. Supplement to the Ophiuridæ and Astrophytidæ by Theodore Lyman. 17 pages. 2 plates. Large 8vo. 1871. Cambridge.

How Plants Behave: How they Move, Climb, Employ Insects to Work for them, etc. By Asa Gray. Forming Part 2 of Botany for Young People. 12mo, board, pp. 46. Illustrated. New York and Chicago: Ivison, Blakeman, Taylor & Co. 1872. (75 cts. Naturalists' Agency.) Entomological Contributions, No. 2. By J. A. Linter. Svo pamph, pp. 66. Albany, 1872. On the Structure of the Skull and Limbs in Mosasauroid Reptiles, with Descriptions of New Genera and Species. By O. C. Marsh. Svo pamph. pp. 21. 4 plates. June, 1872. Early Stages of the American Lobster. By Sidney I. Smith Svo. pp. 6. 1 plate. June, 1872. Le Naturaliste Canadien. Vol. iv. No. 6. La Revue Scientifique. Serles 2. Nos. 46-49,