December 24, 1909] 



SCIENCE 



927 



quency of its mounds on given areas. The 

 text and drawings are based partly on allied 

 species inhabiting Colorado and California. 

 Several pages of the text are devoted to its 

 utility in making loam, and incidentally to 

 showing the fallacy of Darwin's assumption 

 that earthworms are found throughout the 

 world, and are the chief agency in soil forma- 

 tion. Although in vast regions of the interior 

 of North America there exists a stratum of 

 humus, sometimes several feet in thickness, 

 " earthworms are not native to any part of 

 America south of the Great Slave Lake or 

 west of the immediate Mississippi Valley," 

 execept where they have been introduced. 



This detailed, topical method of treatment 

 is followed throughout the book, the illustra- 

 tions varying with the character of the species 

 treated, and include details of structure, poses 

 of the animal, plans of runways, tracks, bur- 

 rows, excrement (scatology), means of de- 

 fense, etc. 



The illustrations are usually the author's 

 own, from sketches from life or from nature, 

 the exceptions being usually skulls, which are 

 mainly copied (with acknowledgments) from 

 technical papers issued by the Biological Sur- 

 vey. The maps are the result of careful re- 

 search, the ranges being compiled from the 

 literature of the subject plus the author's per- 

 sonal information, the actual places of known 

 capture being often indicated by dots within 

 an admittedly hypothetical outline of the sup- 

 posed range. 



The author sticks closely to his text — the 

 habits of the animals — to the exclusion of 

 hunting stories and incidents of travel. Al- 

 though the work is so voluminous the style is 

 graphic and concise; the matter is pertinent 

 and well stated, and there is no padding. 

 There are some quotations from previous 

 authors, some previously unpublished infor- 

 mation from correspondents, credit for facts 

 and data, published or unpublished, being 

 bounteously given, but the great bulk of the 

 matter is a record of the author's own observa- 

 tions and field explorations, carried on for a 

 long series of years and over a wide range of 

 country. As a contribution to the life his- 



tories of North American mammals it is with- 

 out a rival, and beyond comparison the best 

 work of its kind that has ever been written. 

 Indeed, it is safe to say that nothing having 

 the same scope and detail, either in text or 

 illustrations, has ever before been attempted. 

 These two ponderous volumes are a monument 

 to the author's persistence and zeal through 

 many long years of affectionate search for 

 knowledge of the habits and intimate home 

 life of our American mammals, to which the 

 publishers have contributed a setting worthy 

 of the subject. 



J. A. Allen 

 Amebican Museum of Natlbal Histoby, 

 New Yobk City 



The Green Bug and Us Natural Enemies. 



By Professor S. J. Hunter. Bulletin of 



the University of Kansas, Vol. IX., No. 2. 



This, the most voluminous study of the 

 parasitism of a plant louse thus far reported, is 

 worthy of careful attention. The rapid spread 

 of the recently imported Toxoptera graminum 

 from Europe is well presented and the illustra- 

 tions vi the structure of this and the related 

 native species are quite satisfactory. The 

 most useful parts of the work are the elab- 

 orate breeding experiments both on the plant 

 louse and on its most abundant parasite Lj/si- 

 phlelus tritici. Indeed, the publication af- 

 fords the best data we have at hand for the 

 discussion of the question of the efSciency of 

 parasites. Not a little of the work is devoted 

 to a defense of the author's claims as to the 

 results of an aggressive campaign in which 

 he distributed nearly 9,000 boxes of these 

 parasites. 



The author is very thoroughly convinced 

 that the parasites were effective, saying (p. 8) : 

 " That this parasite not only controlled, but 

 in many cases practically exterminated, the 

 green bug last season, no one questions," and 

 (p. 24) : " Professor Glenn on the basis of 

 twenty-five fold increase estimates that one 

 female parasite placed with 2,000 adult green 

 bugs just beginning to reproduce would ex- 

 terminate them in twenty-five days, and one 

 female with 10,000 such adults would exter- 

 minate them in thirty days." 



