1142 The American Naturalist. [December, 
author has been assisted by Mr. G. C. Davis. Prof. Cook describes 
under separate headings three formule for preparing the emulsion : the 
first is his own metliod of making an emulsion of soft soap and kero- 
sene ; the second, his method of making an emulsion of hard soap 
and kerosene ; and the third is the well-known Riley-Hubbard formula. 
For success with the latter the experiments here reported indicate that 
soft water must be used. Th authors believe the pyrethro-kerosene 
to be avaluable insecticide, and report experiments in which kerosene 
emulsion has been successfully used against vermin on domestic 
animals, rose chafers, hollyhock bugs (Orthotylus delicatus Uhle.), 
yellow-lined currant bugs (Pecilocapsus lineatus Fab.), immature 
‘squash bugs, aphides, pear slugs, and pea weevils. The Bulletin is 
illustrated by eight original figures, and altogether is one of the most 
useful and interesting of recent station publications. 
Host-Plants of Aphididez.—Mr. T. A. Williams nas lately pub- 
lished as Bulletin No. 1 from the Department of Entomology of the 
University of Nebraska a ‘‘Host-Plant Index: of North American 
Aphidide.’’ There isa short introductory discussion of plant lice by 
rof. Lawrence Bruner, after which follows a list of North American 
plants and the species of Aphides which attack them. 
Prof. Smith on the Rose-Chafer.—Bulletin No. 82 of the New 
Jersey Experiment Station consists of an extended discussion of the 
rose-chafer or ‘‘rosebug’’ (Macrodactylus subspinosus) by Prof. J. B. 
Smith, who states that ‘this insect has done more injury during the 
few years last past than any one other species in the state of New Jersey, 
excepting, perhaps, the codling moth and plum curculio.’’ The 
author gives under successive headings an account of its history in 
New Jersey, food habits, mouth parts, habits of the beetle and larva, 
breeding grounds, life history, and remedi Under the latter head- 
ing he reports experiments showing that a practical purposes in a 
region where the insect is so abundant the following substances have 
little or no, remedial value: the arsenites, coppér mixtures, pyrethrum, 
kerosene, lime, tobacco, acetic acid, quassia, digitalis, corrosive subli- 
mate, muriate of ammonia, cyanide of potassium, ‘¢ odorless insecti-. 
19 
cide,’’ sludgite, kainit, alum, and hot water. The latter substance, 
which has lately been recommended by the Rural New Yorker as a 
rosebug remedy, was found to kill the beetles at a temperature of 
125°, but the difficulty of applying it successfully was so great, \on 
account of the cooling caused by evaporation, that it proved a failure 
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