PREFATORY NOTE. 
The report herewith submitted was originally planned in 1885 as a 
conjoint work with Dr. C. V. Riley, the intention being that the writer 
should make a first draft of the matter, presenting the results of his 
own studies, and that the material should then be reviewed by Dr. 
Riley to make such corrections and additions as the material in his 
hands might permit. On this basis, manuscript was prepared and 
transmitted to Washington at intervals up to 1890, but the numerous 
duties of Dr. Riley, especially his work for the Paris Exposition in 
1889, prevented his giving any attention to this matter, and in 1890, at 
his suggestion, the chapter on “ Pediculi and Mallophaga,” which had 
been my special study, was put in shape for the press and issued 
shortly after as Bulletin 7 of the series of Division Bulletins. The 
other matter was held in reserve, though receiving attention at times 
when other work permitted. 
After Dr. Riley’s death his successor, Dr. Howard, found the writer’s 
incompleted manuscripts and proposed that they should be revised, 
completed, brought up to date, and published—a proposition which I 
was very glad to accept, as it seemed after so much of my time had 
been given to this work while in the employ of the Division of Ento- 
mology it was but right that there should be some published results. 
In completing the work the original plan and scope has been followed 
in most respects, but it has been found necessary, on account of the 
mass of material collected, to restrict the treatment of the species, 
giving special prominence only to those forms of interest to the Amer- 
ican stock breeder and poulterer, and especially in the bibliography to 
limit the titles. 
While a large number of the figures have been prepared expressly 
for this work, a number have been secured from other sources, and will 
be found duly credited in each instance. Of the original figures, 34, 
36, 50, 51, and 52 were prepared in the Division of Entomology; the 
others have been drawn by Miss Charlotte M. King, under my personal 
Supervision. ji 
I take this opportunity to acknowledge my indebtedness to Professor 
Riley for his interest and assistance in the inception and preparation of 
the report, and to Dr. M. Francis, Prof. 8. A. Forbes, Dr. A.S. Packard, 
Prof. Lawrence Bruner, Dr. A. Hassall, Prof. J. H. Comstock, Mr. C. F. 
Baker, Mr. 8. E. Cassino, and others who have kindly aided me with 
the use of cuts or with specimens for study. To Dr. L. O. Howard I 
am under especial obligations for most valuable aid in the final revision 
and completion. He has taken great pains to furnish me references 
not otherwise at command and to provide illustrations. 
HERBERT OSBORN. 
Iowa Agricultural College, Ames, Iowa. 
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