1890.] Entomology. 1091 
visible, and in which identification to any but the specialist, or to one 
with a large collection, was all but impossible.’’ Professor Smith has 
greatly restricted the genus Agrotis, leaving but eight species in it, and 
has proposed for the others a number of new genera, based on definite 
structural characters. He has also used seven existing generic names, 
The revision is based on a study of nearly all the important collections 
of the country, and covers nearly 250 pages. 
In the introductory paragraphs we find this significant remark: “I 
had at one time the strong conviction that genera were natural assem- 
blages, capable of strict limitation and definite in extent. The study 
of very large material $ince that time has convinced me that my first 
impression was erroneous, and that genera as such are mere artificial 
divisions of convenience, useful for the purpose of identification, and 
for the expression of relationship, and that they were useful for that 
purpose just in proportion as they expressed clear and definite associa- 
tions of characters.’’ * 
The White Grub.—In the June (1890) Crop Report of the 
Illinois State Board of Agriculture Prof. S. A. Forbes reports having 
demonstrated that ** the current life-history of our common white grub 
is mistaken. All our most abundant species complete their growth as 
grubs in midsummer or early autumn, and form both pupa and adult 
beetles the same season, hibernáting in the earth in this last stage, and 
coming out in May or June of the next year. Where these grubs are 
injurious in the fall they may be expected, as a rule, to be even more 
destructive in the same fields the following spring.” 
Professor Forbes also announces having obtained evidence that 
there may be four generations of the Hessian fly, which attack wheat 
with destructive effect, —two in spring and two in autumn, 
Nematodes in Australia.— The August issue of the Agricultural 
Gazette, of New South Wales, is devoted to a discussion of N 
injury to root crops by Professor N. A. Cobb. It is divided into three 
sections,—the first treating of the life-history of Zy/enckus arenarius ; 
the second describing twenty-four species of the genus Tylenchus, with 
which the author unites Heterodera ; and the third discussing the dis- 
ease and its remedies. This paper will be of great value to all engaged 
in studying these little creatures. 
Miss Ormerod’s Manual.—A new and greatly-enlarged edition 
of Miss Eleanor A. Ormerod’s admirable Manual of Injurious Insects 
has lately been published. The new work forms a volume of over 
four hundred pages, the mechanical execution of which is altogether 
