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 C. V. Eiley, 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. Beports (1 to 14) on the noxious, beneficial, and other Insects of the Slate of 

 Netv 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 fValdverderber undihre Feinde {Forest Destroyers and their Enemies). Ber- 

 lin, 1841. 8vo. Sixth edition; 1869. 



Die Waldverderbniss oder dauernder Schade, welcher durch Insektenfrass, Schdlen, 



Schlagen, und Verbeissen an lebenden Waldbdumen entsieht (Forest injury or 

 losses inflicted by insect attacks, etc.). 4to. 2 parts. Berlin, 1866-'68, 

 with many colored plates. (A magniticent 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-Europdischen Foratinsektenkunde. Wien, 

 Part I, 1885. Part II, 1889. 8vo. 

 (Compare also the works of Perris, Taschenberg, Eichhoflf, 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: 



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