PREFACE. 



In the course of more than three years' work with the parasites 

 and natural enemies of the gipsy moth and brown-tail moth, nearly all 

 imported from Europe or Japan, it has been necessary to work with a 

 number of species new to science and to make the most careful life- 

 history observations upon all the species concerned in order to 

 ascertain points of possible importance in the practical handling of 

 the material. It is proposed in this Technical Series No. 19 to include 

 a series of short papers giving some of the systematic and biological 

 results of this work, the practical deductions for the most part being 

 reserved for consideration in the bulletins of the general series. 



Technical Series No. 12, Part VI, entitled "A Record of Results 

 from Rearings and Dissections of Tachinidae," by Charles H. T. 

 Townsend, published September 18, 1908, really should have started 

 this Technical Series No. 19, since it directly concerns itself with 

 results of work at the gipsy-moth parasite laboratory. 



The laboratory in question, it should be stated, is now stationed at 

 Melrose Highlands, Mass. (No. 17 East Highland Avenue). It is 

 conducted with the cooperation of the State of Massachusetts and 



the United States Department of Agriculture. 



L. O. Howard. 

 January 28, 1910. 



