The family known heretofore as Blepharoceride appears as Liponeuridæ. This change of name was made by Osten Sacken several years ago. He has more recently abandoned the change in a published paper, and there seems no reason why the old name should be displaced. The families Xylophagidae and Conomyidæ are united with Leptidæ, thus simplifying the family and generic diagnoses. This seems a rather surprising arrangement, yet may be logically defended.

The family Lonchæide is united with the Sapromyzida. Aside from these changes there are no important differences in the higher categories between the last catalogue and the present work.

While the printing and binding are excellent, there are a number of typographical errors especially in the spelling of generic names, as for instance in Subulomyia, p. 43, the list of lepidopterous genera on p. 146 (five mistakes) and the list of Tachinid and Dexiid genera, p. 147 (four mistakes). But few of these, however, are more than the interchanging or omission of a letter.

This book is Dr. Williston's most important single contribution to dipterology thus far, and it worthily exhibits the industry, experience and ability of the author, which have secured for him world-wide recognition as a dipterist of the highest rank.-J. M. ALDRICH, Moscow, Idaho.

Color Variation of a Beetle.-Mr. W. Baterson gives an account of his statistical examination of the color variations of the beetle Gonioctena variabilis, which appears to be abundant in hilly places in the south of Spain. He finds that we have here to do with a species whose members exhibit variation in several different respects, and that the variations occur in such a way that the individuals must be conceived as grouped round several special typical forms. There is thus not one normal for the species but several, though all live in the same localities under the same conditions, and though they breed freely all together these various forms are commoner than the intermediates between them. Some time since, when calling attention to the excessive variability of the color of Coccinella decempunctata and the no less striking constancy of C. septempunctata which lives with it, Mr. Bateson remarked that to ask us to believe that the color of the one is constant, because it matters to the animal, and that the other is variable because it does not matter, is to ask us to abrogate reason. Mr. Wallace, it seems, is of this very opinion; but he does not explain how it is that the color of one is so important, and the color of the other unimportant to the beetle. (Journal Royal Microscopical Society.)

American Nematinæ.-The third of the technical series of bulletins from the U. S. Division of Entomology is entitled "Revision of the Nematinæ of North America, a Subfamily of Leaf-feeding Hymenoptera of the Family Tenthredinidæ." It is by Mr. C. L. Marlatt, and extends over 135 pages, with one excellent plate and several illustrations in the text. We quote from the introduction as follows:

"The subfamily Nematina of Thompson or Nematina of Cameron (Konow's subtribe Nematides) comprises a very large group of closely allied species, distributed in the classification adopted by the author among nearly a score of genera. They range from very small insects to medium sized, but include no very large species, or in length from 2 to 12 mm. They are for the most part smooth, shining, and rather soft bodied, and are variously colored, but yet presenting frequently a confusing similarity in general form, and particularly in coloration, rendering their generic and specific references in some cases difficult. In point of number of species and abundance of individuals this subfamily far exceeds any other of the corresponding groups in the family Tenthredinidæ, and in variation and peculiarities in larval habits and in economic importance many of the species belonging to it have a very great interest.

"Geographical Distribution.-The Nematinæ are distinctly northern in their range, reaching their greatest development in abundance of species and specimens in the transition and boreal zones, and extend northward into the circumpolar regions-species occurring abundantly in Greenland, Iceland, and Spitzbergen. Southward they become less and less numerous, and are particularly wanting in tropical countries. This is illustrated very forcibly in Europe by the occurrence of over 70 species of the old genus Nematus in Scotland (Cameron) and 95 in Sweden (Thompson) as against 12 about Naples, Italy (Costa); and the same discrepancy exists between the temperate and subarctic region of America and the Southern States and Mexico.

"Food-plants. Their food-plants cover a wide range, some species affecting grasses, one or two very destructive to the grains, others various deciduous trees and shrubs, and still others conifers. The majority of the species occur, however, on plants of the families Salicaces, Betulaceæ, Rosacea, and Coniferæ, in the order given.

"Life history and habits.-The Nematines are among the first sawflies to appear in spring, occurring abundantly on trees on the first appearance of the leaves. They do not often frequent flowers, except, at least, those of the plants upon which their larvæ feed. Many willow species, for example, occur abundantly on the earliest spring bloom of the

willow. In common with other sawflies, however, they rarely leave their larval food-plants, and to be collected successfully a knowledge of their habits in this respect is very desirable.

"In number of broods great diversity is found, and the normal rule of most Tenthredinidæ, of a single yearly brood, is frequently deviated from. Some species are known to be limited in number of broods only by the length of the season, as, for example, Pteronus ventralis Say, the common willow species. Two annual generations are common, but many species are single brooded, the larvæ entering the soil or other material or remaining in their galls at the completion of growth and continuing in dormant condition until the following spring, when shortly before they emerge as perfect insects the change to the pupal condition takes place. The males normally appear a few days before the females, and the duration of the life of the adults of both sexes is short, not often exceeding a week or ten days. Of a large percentage of the species no males are known, and in the case of many species careful and repeated breeding records indicate that males are very rarely produced.

"In some species parthenogenesis is complete; that is, the eggs from unimpregnated females produce other females. In other instances of parthenogenesis, however, either males only are developed from unfertilized ova or females very rarely.

"The union of the sexes takes place very shortly after the appearance of the females, and egg deposition closely follows. The eggs are inserted either singly or a number together in the young twigs, larger veins, petioles, in the surface parenchyma, or in the edges of the leaves, the single exception being the case of the gooseberry sawfly (Pteronus ribesii), which merely glues its eggs to the leaf without making any incision whatever.

66

'Most of the species are external feeders on the foliage of plants, but the species of two genera, Euura and Pontania, so far as their habits have been studied, are gall makers, and pass their early life in the interior of the plants, either in the stems without causing abnormal growths or in the excrescences or galls on the stems and leaves. At least one American species develops in the rolled or folded edges of the leaf. The larvae are 20-footed, some solitary, others gregarious-the latter usually more brightly colored and possessing means of protec tion in glands secreting a noxious fluid. Most of the solitary ones are green and not readily observed. They usually feed from the underside of the leaves, eating from the edge or cutting circular holes in the general surface, and in some cases taking everything but the stronger. veins. Many species rest quietly during the day, feeding only at night.

Some have the habit of throwing the posterior segments violently upward to frighten away parasites or enemies; others adhere to the leaves or twigs by the thoracic feet only, coiling the posterior segments under the middle ones."

Entomological Notes.-Prof. F. L. Harvey monographs in an elaborate manner the Currant Fly, Epochra canadensis, in the report of the Maine Experiment Station.

The North American species of Nemobius are monographed by Mr. S. H. Scudder (Journ. N. Y. Ent. Soc., Sept., 1896). Several new species are described.

Mr. Alex. D. MacGillivray has recently monographed the American species of Isotoma in the Canadian Entomologist

In the check-list of the Coccida published by Prof. T. D. A. Cockerell, in the Bulletin of the Illinois State Laboratory of Natural History (vol. IV, pp. 318-339) 773 species are listed.

A number of new species of Scarabeidæ are described by Martin L. Linell in the Proceedings U. S. National Museum (vol. XVIII, pp. 721-731.

Prof. J. B. Smith discusses again the San José Scale (Aspidiotus perniciosus) in Bulletin 116 of the New Jersey Station.

"The Principal Household Insects of the United Stated" is the title of the extremely valuable and interesting Bulletin No. 4 of the Divis ion of Entomology, U. S. Dept. of Agriculture. It was prepared by Messrs. Howard, Marlatt and Chittenden.

The Lamiina of North America are monographed by Messrs. C. W. Leng and John Hamilton, in the Transactions of the American Entomological Society (vol. XXIII, No. 2). In the same issue Mr. William H. Ashmead describes a large number of new parasitic Hymenoptera. Mr. F. M. Webster discusses the Chench Bug in Bulletin 69 of the Ohio Experiment Station, and several destructive insects in Bulletin 68.

The Phylogeny of the Hymenoptera has recently been discussed by Mr. Ashmead in an interesting and authoritative paper in the Proceedings of the Entomological Society of Washington (vol. III, No. 5).

EMBRYOLOGY.'

Movements of Blastomeres.-In a copiously illustrated and extensive paper on the cleavage of Ascaris megalocephala Otto zur Strassen' lays special emphasis upon certain movements of the cells of the embryo.

In the living egg most remarkable rearrangements of the material are easily seen when the first four cells glide over one another. In later stages changes in form are traced to movements of the cells that must have taken place though not actually seen but inferred from a very detailed study of preserved material. The author confined his attention chiefly to the ectodermal layer of cells and knowing the pedigree of a very large number of them was able to affirm that the changes in shape that the embryo exhibits are due, in part at least, to an actual migration or rearrangement of cells. Cell division and surface tension are not the only factors concerned in this change of position of the cells; there must be some individual movement of certain cells.

This movement of the cells is regarded as being of the same nature as that observed by Roux in the isolated cells of the frog's egg and is, therefore, designated Cytotropism.

The production of form in the development of the Ascaris embryo has then this important factor-a power of cells to move towards one another and thus change the shape of the entire mass. This movement is in addition to any purely mechanical movements due to surface tension and is due either to attraction between cells or to repulsion between cells. In either case it is assumed that chemical influences are at work: that this movement arises from chemotactic strains.

The movements are much restricted in that a cell travels its own length at most and is never free from its sister-cell. In fact the two cells that arise from the division of one remain connected and are not to be separated by any intrusion of migrating cells and the author thinks that the movements are probably even more restricted in being merely the rearrangements of two groups of such sister-cells both derived from one parent, being merely readjustments of four grandchildren of one cell! The entire ectoderm may then be regarded as a mosaic of such sets of families of four, each having its own internal readjustments.

Edited by E. A. Andrews, Baltimore, Md., to whom abstracts reviews and preliminary notes may be sent.

' Archiv f. Entwickelungsmechanik, 3, 1896, pps. 27-101, 133--188, Pls. V--IX.