OUTLINES OF COMPARATIVE EMBRYOLOGY ; 
Or, Lire HISTORIES OF ANIMALS, INCLUDING Man. By A. 8. Pack- 
ARD. Copiously Illustrated. 8vo. $2.50. 
“An angle work of reference for advanced students. . . . . It would not be 
easy to find a work on the branch of Animal Physiology of which it treats, which dis- 
plays such acute and delicate analysis, or presents a more complete statement of the 
recondite facts.”’— Tribune. 
‘*Must remain for many years the one standard work on the subject. . . . Alto- 
gether it forms one of the most valuable works of science yet published in this coun- 
try, and it is safe to say that no working naturalist can do without it.”—Prof. E. S. 
MorszE, in Popular Science Monthly. 
“Tt occupies worthily an important place absolutely unfilled to this time.”—Chan- 
cellor WINCHELL, 
GUIDE TO THE STUDY OF INSECTS, 
AND A TREATISE ON THOSE INJURIOUS AND BENEFICIAL TO CROPS. 
For the use of Colleges, Farm-Schools, and Agriculturists. By 
A. 8. Packarp, M.D. With 11 Plates and 650 Woodcuts, 
Eighth edition. $5. 
“Thold that your work ought, in connection with Harris’s ‘Treatise on Insects 
Injurious to Vegetation,’ to whichit is, as it were, the key, to be introduced in all our 
pees colleges, as the best text-book of that kind now extant.’”—Professor L. 
GASSIZ, 
“Your ‘Guide to the Study of Insects’ has become the text-book up here.”—G, 
Crores, Librarian of Cambridge University, England. 
“ But it is of its scientific merits especially we wish to speak, and of which we can 
speak in no qualified terms of praise. The first two parts are, we do not hesitate to 
affirm, the best things of the kind that our language possesses. . . . . We havo 
seldom fallen on so thoroughly good a scientific treatise, and we can only conclude 
our notice of it by advising all our natural history readers to make its acquaintance. 
There is no work we should prefer to it as a book for the student. "Scientific Opin- 
ion, London. 
* Among the best guides to the study of insects which at present exist in our liter. 
ature.”’—Dr. A. Dourn, in the Entomological Journal, of Stettin, Prussia. 
“The study of Entomology is one that can be almost as easily pursued in the 
school-room as Botany, and we should be glad to see the experiment tried. Dr. 
Packard's work is well fitted, by its clear, simple style, for use as a text-book.””— The 
Michigan Teacher. 
“In typography and illustrations the part before us leaves nothing to be desired, 
while the author’s style is very perspicuous. We hope the work will be used as 
intended, in colleges and farm-schools and by agriculturists. . . . . . In every 
articular of text, illustrations, and manufacture, it is thoroughly well done.’’— The 
‘ation. 
* Altogether, we are immensely pleased with this work. It is assuredly, all in all, 
the fullest, most modern, and most clearly-written treatise on insects we have ever 
seen.”’—Popular Science Review, London. 
“The most recent memoirs connected with these subjects have been made use of 
by the author, and this part of his work is certainly the best, manual of entomology 
which the English reader can at present obtain.”—Wature, London. 
‘‘As a practical treatise on American entomology, with reference especially to the 
insects injurious or beneficial to crops, it stands almost alone, and reflects the Leg 
credit upon American scholarship, patience, and scientific skill."—New York Tribune. 
HENRY HOLT & CO., Pusiispers, NEW YORK, 
