1926 ] 
Book Review 
27 
It is to be desired that a test of this kind be applied to the 
American relatives of these flies, for it is quite probable that 
their differences may have a similar hereditary basis. 
Conclusion. 
The results obtained by Gabritschevsky in studying the 
relationships between Volucella bombylans, var. bombylans, V. b. 
plumata and V. B. hcemorrhoidalis agree very closely with ratios 
expected upon a mendelian interpretation, a condition hardly to 
be predicted from an undetailed perusal of the genetical data as 
presented by this experimentor. 
Book Review. 
Manual of Injurious Insects, By Glenn W. Herrick. Henry 
Holt & Co., New York City, 1925. $4 . 50. 
This is a book of 489 pages including its index, with 458 
text-figures. It deals mainly with the more abundant North 
American insects that affect agricultural crops although there are 
short chapters dealing with the parasites of poultry and livestock 
and a few words on the relation of insects to human and animal 
diseases. It includes also a rather elaborate consideration of 
insecticides and the machinery for applying them. Forest insects 
are entirely omitted. 
The several pests are dealt with seriatim , classified according 
to the crops upon which they feed. For each species there are 
paragraphs entitled “ Description: Injury; Life history, and 
Control measures,” together with a figure of the insect or its 
work and a list of such useful practical literature as has been 
published by the Federal government and the various state 
agricultural experiment stations. Less common pests are listed 
by their common and scientific names with references to economic 
literature. 
Professor Herrick’s book forms a useful compendium and 
with its abundant references will also furnish a key to the lit- 
erature for those who wish to learn more concerning certain 
species. 
