ie 
Hastman Kodak Co., Rochester, N. Y., Photomicrogranhy. 5th ed. 36 p., 
a1iius., diagra. Rochester, N. Y., 1919. 
Hand, T. E., and Cockerham, K. L. The sweet potato - a handbook for the 
practical grower. 261 p., illus. (Rural Science Series.) New 
York, The Macmillan Company, 1921. 
Insects affecting sweet potatoy p. 137-154. 
Diseases of the Sweet potato, p. 155-169, 
Insecticides, fungicides and spraying machinery, p. 170-176. 
Hardy, M. E. The feography of plants, 327 p., illus., maps. Oxford, 
Clarendon Press, 1920. 
Hess, Richard, and R. Beck, Der forstschutz.....4aufl. 2 vols., illus., 
plates, Leipzig und Berlin, Druck und Verlag von G, B. Teubner, 
1914-16. 
Hilger, Adam, ltd., pub. Optical methods in control and research labor- 
atories. 30 p., illus. London, 1920. 
Bibliographies and bibliographical footnotes interspersed. 
Hitchcock, A. S. A manual of farm grasses. 175 p.,rfllus. Washington, 
ee do 
Leng, C, W. Catalogue of the Coleoptera of America, north of Mexico. 470 
Pp. Mount Vernon, N. Y., John p. Sherman, Jr., 1920. 
Catalogue of the North American Coleoptera described as fos= 
sils, by H. F. Wickham, p. 347-365. 
Bibliography of taxonomic coleopterology to January 1, 1919, 
P. 367-444, 
Ritchie, James, The influence of man on animal life in Scotland - a Study 
of faunal evolution. 550 p., illus., plates, maps. Cambridge, At 
the University Press, 1930. 
Camp followers of commerce or animals, introduced unawares, 
p. 4174475, 
Russell, H. L. Agricultural bacteriology for students in general agricul- 
ture, by H. Lt Russell ... and E. G, Hastings, 368 p., illus., map. 
(The Century Agricultural Series.) New York, 1921. 
Schmidt, C. C, Nature study and agriculture. 459 p., illus. Boston, 1920. 
Books, pamphiets and periodicals for reference, p, 439-448. 
Schoyen, @. H. i.e. Worway~Stat-Ent. Beretning om skadeinsekter og 
plantesykdommer i land og havebruket-1919. 52 p., illus Kristiania, 
Grondahl & Spes boktrykkeri, 1920. 
Smith, J. W. Agricultural zetSrology, the effect of weather on crops. 
304 p,, illus. New York, Macmillan, 1920, (Rural Textbook Series.) 
References at ends of chapters, 
Stevens, F. L. Diseases of ecomomic plants, by F. L. Stevens ..,. and J.G. 
Hall... Rev, ed. 507 p., frong. (port.) illus. New York, 1921. 
& Bibliograpny,pp. 467-490, 
