4 Preface 



The first part, a catalogue of the gall-making Cynipidae, is published practically as he left it. The 

 second part, a supplemental catalogue of gall-producing organisms, was assembled from the orig- 

 inal notes by Dr. Thompson's father, the late S. Millett Thompson, who is also responsible for 

 the selection and grouping of the illustrations on the plates. The work as planned by Dr. Thomp- 

 son was to be a catalogue and handbook; that relating to the New England forms being based 

 largely upon original studies. The editor has confined himself to the elimination of a few obvious 

 errors and has endeavored to reproduce the work substantially as projected by its author. Ref- 

 erences to plates have been inserted throughout the text, descriptions of the plates written and 

 and the correct synonymy indicated wherever it seemed advisable or necessary. The original 

 names used in the manuscript have been allowed to remain and where more recent terms are 

 suppHed or determinations made -by the editor, such matter invariably appears in smaller 

 (8 point) type. Dr. Thompson's collection of galls is deposited with Clark University. 



