INTRODUCTION. 
The subject of Forest Insects is almost a distinct branch of economic 
entomology, and little special attention has been given to it as yet in 
this country, owing to the fact that our entomological students have 
been obliged to concentrate their efforts upon the more destructive 
garden and field insects. 
The special works on this topic are, though few, notable for the 
extensive research and care with which they have been prepared; hence 
their permanent value. By far the most important are the voluminous 
works of Dr. J. T. C. Eatzeburg and those of Perris, Eichhoff, and 
Kaltenbach, while an excellent general work on forest insects is that 
of Judeich and Nitsche. The following list of works bearing directly 
on this topic, and indispensable, should be supplemented by the reports 
and articles of 0. V. Kiley, J. A. Lintner, J. H. Comstock, S. A. Forbes, 
and others : 
T. W. Harris Treatise on some of the Insects injurious to Vegetation. Third edition; 
illustrated. Boston, 1862. 
Asa Fitch. Reports (1 to 14) on the noxious, beneficial, and other Insects of the State of 
Keiv York. Albany, 1856-'70. 
V. Kollar. A Treatise on Insects injurious to Gardeners, Foresters, and Farmers. Trans- 
lated from the German by J. and M. Loudon. London, 1840. 
J. T. C. Ratzeburg. Die Forstinsekten, etc. (Forest Insects). Berlin, 1839, 1840, and 
1844. 4 vols. 4to, with many plates. 
Die Ichneumonen der Forstinsekten, etc. (Ichneumons of Forest Insects). 3 parts. 
Berlin, 1844, 1848, and 1852. 4to. Plates. 
Die Waldverderber undihre Feinde (Forest Destroyers and their Enemies). Ber- 
lin, 1841. 8vo. Sixth edition ; 1869. 
Die Waldverderbniss oder dauernder Schade, welcher durch Insektenfrass, Schalen, 
Schlagen, und Verheissen an lebenden Waldbaumen entsteht (Forest injury or 
losses inflicted by insect attacks, etc.). 4to. 2 parts. Berlin, 1866-'68, 
with many colored plates. (A magnificent and most useful work.) 
A.S.Packard. Guide to the Study of Insects., Ninth edition ; 1888. 8vo. New York, 
H. Holt & Co. 
Judeich und Nitsche. Lehrbuch der Mittel-Europaischen Forstinsektenkunde. Wien, 
Part I, 1885. Part II, 1889. 8vo. 
(Compare also the works of Perris, Taschenberg, Eichhoff, Kaltenbach, Altum, 
Nordlinger, Henschel, and others.) 
While the reader is referred to the ordinary text books for the ele- 
ments of entomology, the following facts may prove serviceable in 
connection with the subject of forest entomology : 
5 
