INSECT

the basis for successful implementation of chemosterilization techniques. Although these data are theoretical and/ or hypothetical in nature, it is obvious that they are necessary for one to fully understand the potential of sterility techniljues from the applied standpoint. While insect sterilization is the main topic of discussion, the fact that the sterility principle could be used for regulating vertebrate pest populations also is considered.

pastures, and other limited areas hand methods are more economical and effective than other methods of control.
Ecological. Spring weather is probably the most important natural check for the pests. Warm weather in April or early May that induces hatching followed by a week or more of cool weather frequently destroys the caterpillars. One or two such seasons are usually ample to reduce the pests to insignificant numbers. It is probable that weather is the dominant factor in production of the cyclic abundance of these pests. LITERATURE  In this inexpensive volume, intenclcd by the author to help fill tho gap between the frequently all to sketchy unclergrailuate insm~ctions and the morc expensive references, the commoner metlloils employed in rnicrotecI~nique are outlined in a simple manner, along with thc principles involved. The customary chapter on the micl-o~cnp~ includes a ~inlpIc rnetllod of dark ground iIlumination. The chapters on terhnique incluile s~i c l~ subjects as parallin embedding, methods for \ peciIic materialc, rormulae and hints, and sourcrs, cl~lutre, and ~>rc.sert.ntinn nf material.
Al~hough this vcllume contains very little specific information on technical proceclurea Cor tise with iniect material, it is a handy little volume for those cominenci 1 1~ micrutecliniquc.
Students of Entomology generally will be grateful to Dr. G. W. Herrick for preparing this new edition. Probably no I>ook in North ~Zmerica has had more influence on the training of entomoliogwts in Ll~e United States and Canada than the early editions of this work. The fact that it has gone through several editions indicates the place it occupies among entomologists. It is, indeed, much more than an introduction to entomology; it is by many, I feel sure, regarded as one of our most valuable guides and works of reference, as it contains information of value to all workers, regardless of age. During my many years of government service, a book which I have consulted freely is my copy of one of the earlier editions. It has helped me on many an occasion. Entomology is now recognized the world over as one of the more important of the natural sciences. Its development during the last few decades has been truly remarkable. I n the future, it is fully expected that this developmept will be even more remarkable. I n this progress, Comstock's "Introduction to Entomology" will assist in no small way in the education of students who decide to enter chis field of research. It should, therefore, be available to all who make, this decision.
Considerable additional information is included in the new edition. In view of the increasing interest in the subject of the biological control of insects, the discussions relating to parasitic species occurring in the Hymenoptcra have been extended considerably. With these Dr. Herrick has harl the assistance of Dr. Henry K. Townes.
In such an important work as this, we would like to have seen some of the older illustration5 replaced by better ones, and, in rhe discussions of the Lepidoptera, changes in the nalncs o[ species madc to cor~rorrn to those used in McDunnough's check list of the Lcpidoptera oC Canada and the U n i~e d State$. These, however, are minor matters. The important achievernenr is the pubIicatian of this new edition of a most valuahlc work, and Ior chis we congratulate Dr. Herrick.
Arthur Gibson

INSECT TRANSMISSION OF PLANT DISEASES.
By J. G. Leach, McGraw-Hill Book Co., New York. Pages 1-XVIII and 1-615. 238 figures. 1940. Price $6.00. I n the course of the past three decades, plant pathologists have become increasingly aware of the importance of insects in the spread and development of plant diseases. The literature of this period contains many references to the role of insects associated with individual plant diseases and groups of diseases. These references vary from a few lines crowded into a paper of a mycological or etiological nature to separate publications oE an excellent cl~aracter such as K. M. (1953). The present volume, however, is the first comprehensive eflhrl 10 assemble the more pertinent facts relating to insect transmission of all types of plant diseases. The experience of the author, formerly professor of plant pathology at the University of Minnesota and at present head of the Department of Plant Pathology and Bacteriology at the University of West Virginia, has enabled him to evaluate these facts and interpret them from the standpoint of practical plant pathology without losing sight of their broad biological significance.

Smith's Recent Advances i n the S t u d y of Plnnt Pirz~res
-Ox necessity the text matter is'-limited to facts concerning insect transmission so that much information concerning plant pathology and vectors has had to be omitted. The list of references at the conclusion of each chapter more Recently I have been engaged in sorting some thousands of North American Carabidae loaned me for study by Mr. David Rockefeller. Among various native species from Quebec was one unexpected stranger, a single $ specimen of Stomzs pumicatus (Panz.) labeled Hemmingford, Quebec, 31-VIII-1916, J. I. Beaulne. The species is a native of Europe, where it has a wide range, including Great Britain and Ireland.
The presence of this beetle in America is almost certainly due to introduction by man. (For discussion of other Coleoptera introduced in eastern Canada, see W. J. Brown, Canadian Entomologist, Vol. 72, 1940, pp. 65-78.) The Quebec specimen agrees well with several from Europe in the Museum of Comparative Zoology. By arrangement with Mr. Rockefeller, the specimen will be deposited in the American Museum of Natural History in New York.
The genus Stomis is previously unknown in America. It is an isolated member of the Pterostichini, distinguished from more typical members of the tribe by unhooked maxillae (cf. G. Horn. Genera of Garahidae, 1881, p. 137).