149 
with the most ferocious ants, and further, that we have a multitude of 
case-bearing Chrysomelide (Cryptocephalus and allied genera) which 
do not live with ants. There is little or nothing known regarding the 
relationship of the myrmecophilous Chrysomelids to their hosts, but it 
is safe to say that the presence of these inquilines is not in any way 
injurious or annoying to the ants, and that the behavior of the latter 
toward the former is friendly, or at least indifferent. 
A COMPENDIUM OF ECONOMIC ZOOLOGY.* 
The European literature is rich in more or less useful manuals of 
injurious or beneficial animals of one class or another, but we do not 
remember having seen a recent work which covers the whole domain of 
economic zoology in so complete a manner as that which has just been 
‘published by Dr. J. Ritzema Bos, professor in the Agricultural College 
at Wageningen, and upon a perusal of this well-illustrated popular 
work we are convinced that it will be extremely useful not only to the 
farmer, gardener, and forester of Germany, for whom it is primarily 
intended, but also to all interested in the economy of animals. The 
nearest approach to this volume which has been published of late is 
Raillet’s Zoologie Médicale et Agricole (Paris, 1886), but this deals more 
with the medical side of the subject. 
The importance of entomology to agriculture in its widest sense 
becomes very apparent from this work, for the insects alone (although 
only those of central Europe are treated) occupy more than one-half of 
the 827 pages of the volume. Some families toward the end of the ento- 
mological portions are treated very inadequately, e. g., the Coccide get 
only two pages; the Pediculi and Mallophaga combined occupy but 
little more than one page; and the Arachnida are not alluded to at all 
among the beneficial animals. The Insecta are generally treated in the 
customary sequence of the orders and families, each of them having a 
Short introduction on general characteristics and development. In 
Lepidoptera, however, the vast number of injurious caterpillars of all 
families are divided primarily according to the food-plants and other 
objects they attack. The clothes-moths are strangely enough omit- 
ted. In the large divisions “deciduous trees” and “coniferous trees” 
further subdivisions are made: first, according to the mode of attack 
(buds, trunk, leaves, etc.), and secondarily, according to structural 
characters of the caterpillars. This renders the whole arrangement 
somewhat awkward and confusing to the untrained reader in spite of 
the references and cross-references given in numbers. The Scolytide, 
Tenthredinide, and Aphidide are treated in the alphabetical sequence 
of food-plants, and here the arrangement is quite perspicuous. 
The condensation of the life-histories is admirably done, and the 
author has not only used the literature but has added largely from his 
* Thierische Schidlinge und Niitzlinge fiir Ackerbau, Viehzucht, Wald- und Gar- 
tenbau, von Dr. J. Ritzema Bos, Berlin (Paul Parey, )1891. 
