48 



THE AMERICAN NATURALIST 



[Vol. XLI 



the seeds have only the maternal color. On the other hand, when the 

 opposite colors are derived from different races, and, especially, when 

 the father is either yellow Hanna or green Petkus, the paternal char- 

 acter shows strongly on the seeds. Consequently, xenia is better 

 manifested in wheats that are not very closely related than in those 

 that are. 



C. B. D. 



ZOOLOGY 



Folsom's Entomology.^ — Dr. Folsom's new work occupies a 

 unique place among entomological text-books. As stated in the 

 preface, "the book was written in an effort to meet the growing 

 demand for a biological treatment of entomology." To this end the 

 systematic side of the subject has been confined to a mere outline of 

 the orders, following essentially the system of Brauer. The external 

 anatomy, too, has been very briefly touched upon as that has been 

 emphasized by the current texts. 



On the other hand, there is an admirably clear-cut discussion of 

 the elements of internal anatomy and of physiology. The value of 

 this chapter lies not only in the careful organization of the material 

 presented but in the omission of a vast amount of detail. The author 

 has followed a common error in stating that the alary muscles are 

 unstriated. He speaks of the follicular cells of the ovary as derived 

 from the primitive germ cells, — a view which is not held by recent 

 investigators of this subject. In view of the decisive work of Petrunke- 

 witsch and otlicr of WcMsinann's students one is surprised to see, p. 

 145, the stntrnirni thai ' males may, of course, result from fertilized 

 eggs, as ill ilic honrv-lHc. according to Dickel." 



The cluiincr on <1( \ clopincnt likewise shows the virtue of vigorous 

 pruning. There is a wry brief but (excellent outline of the embryo- 

 logical development, wliilc tli(^ <ricat( r portion of the chapter is devoted 

 to the postembryonic (Icvclopiiiciit. 



■ Folsom, J. W. Entomology, vnth Special Reference to its Biological and 

 Economic Aspects. Philadelphia, Blakiston's Son & Co., 1906. 8vo, vii + 

 485 pp., with 1 col. pi. and 300 illustrations. 



