102 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
ments along this line and the same is true in other portions of the work. The 
most important change is the addition of a comprehensive and very suggestive chap¬ 
ter on “Insect Ecology,” a phase of biology of fundamental importance to economic 
entomologists. Some 250 new titles have been added to the bibliography, some of 
the less important in the earlier editions being discarded. 
We have in this volume, as in the preceding editions, a most admirable summary of 
the fundamentals of insect biology and ecology with special reference to its ecological, 
really economic applications. In effect it constitutes a ready reference work and 
index to the vast literature summarized in this work. It is an invaluable supple¬ 
ment to our somewhat numerous taxonomic volumes and stands in a class by itself. 
Doctor Folsom has rendered an invaluable service in bringing his work down to date 
and we do not hesitate to commend most highly this latest edition to entomologists, 
especially economic entomologists who should be primarily concerned with biological 
relations and their practical applications. The price of this work is $4.00. 
E. P. F. 
Om Oksebremsens Bekaempelse (Fight against the Ox Warble) by Dr. 
Laust Brodersen. Maanedsskrift for Dyrlaeger (Copenhagen), 
Vol. 34, Pt.13 Oct.,1922. 
The facility with which the ox warbles {Hypoderma spp.) can be greatly reduced 
in numbers is mentioned by the author. The situation of Denmark is favorable to 
entire eradication of this pest in that country provided a concerted fight should be 
made against it. The Minister of Agriculture proposed a law last winter looking 
toward the eradication of the pest throughout the country. While this proposal 
was received favorably by the lawmaking body it was deemed desirable not to press 
its passage at that session owing to the danger of the spread of foot and mouth disease 
by those carrying on the work. 
After discussing the various methods of destroying the ox warble and pointing out 
their difficulties and objections, the author stresses the advantages of an instrument 
for mechanically removing the larvae or grubs, which he and an engineer of Copen¬ 
hagen have perfected. 
The instrument consists of a brass pump about the size of a small garden hand 
sprayer. This is arranged with piston and valves calculated to create a partial 
vacuum. The lower end of the pump is provided with a suction bell of rubber which 
is applied to the animal over the warble hole. As this is firmly pressed against the 
warble the handle of the pump is pulled out and the combined pressure and suction 
removes the larva as well as the pus which surrounds it. He states that in some 
instances the larvae come out with a single stroke of the pump while in other cases 
several strokes are necessary. 
Before beginning extraction the hide on the back of the animal is rubbed with 
soapy water to facilitate extraction. 
The author states that he has tested this device in extracting about two hundred 
and twenty larvae from thirty-five animals in different localities. Most of those ex¬ 
tracted were in the later stages of development but the author believes that the 
younger ones could be removed in the same way. 
The writer of this review is of the opinion that Dr. Brodersen has made a notable 
contribution to this field of work in devising this mechanical warble extractor. 
