16 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



have received a most careful consideration and editorial pruning of 

 the writer. Mr. Fiske, by virtue of his practical residence at the field 

 laboratory and of his intimate charge of all the field notes and labo- 

 ratory notes, has prepared all of the matter in this bulletin relating to 

 the laboratory and field end, subject, of course, to the writer's revision. 

 The rest has been prepared by the senior author. 



Acknowledgements of assistance should be made by the score. The 

 State authorities of Massachusetts, the admirable corps of laboratory 

 and field assistants, and above all the very numerous foreign officials, 

 voluntary assistants, and paid observers have united to make the 

 undertaking possible. Their individual names are all mentioned in 

 the following pages in connection with the parts they played, but the 

 Governments of Austria, France, Germany, Hungary, Italy, Japan, 

 Portugal, Russia, and Spain should especially be thanked in an official 

 publication like this for the assistance given by the officials of these 

 Governments. 



PREVIOUS WORK IN THE PRACTICAL HANDLING OF NATURAL 

 ENEMIES OF INJURIOUS INSECTS. 



Two very thorough and careful general papers on the subject of the 

 practical handling of natural enemies of insects, treating the subject 

 from the different points of view, including the historical side, have 

 been published in the last few years. The first of these, entitled ' l The 

 Utilization of Auxiliary Entomophagous Insects in the Struggle 

 against Insects Injurious to Agriculture," by Prof. Paul Marchal, of the 

 National Agronomical Institute of Paris, was published in 1907, 1 and 

 was partly republished in English in the Popular Science Monthly in 

 1908. 2 The other, by Prof . F. Silvestri, of the Koyal Agricultural School 

 at Portici, Italy, entitled "Consideration oi the Existing Condition of 

 Agricultural Entomology in the United States of North America, and 

 Suggestions which can be Gained from it for the Benefit of Italian 

 Agriculture," was published in 1909. 3 This paper was in part trans- 

 lated into English and published in the Hawaiian Forester and Agri- 

 culturist for August, 1909. Both of these papers should be consulted 

 by persons wishing to inform themselves thoroughly on this question. 

 For the present purpose, treatment of the subject must be brief. 



The study of parasitic and predatory insects is old. Silvestri has 

 pointed out that Aldrovandi (1602) was the first to observe the exit of 

 the larvae of Apanteles glomeratus L. (which he supposed to be eggs) 

 from the common cabbage caterpillar, and that Redi (1668) pub- 

 lished the same observation and another on insects of different 

 species born from the same pupa. A later writer, Vallisnieri (1661- 



i Annals of the National Agronomical Institute (Superior School of Agriculture), second series vol. 6, no. 

 2, pp. 281-354, Paris, 1907. 



2 Popular Science Monthly, vol. 72, pp. 353-370, 407-419, April and May, 1908. 



3 Bulletin of the Society of Italian Agriculturists, vol. 14, no. 8, pp. 305-367, Apr. 30, 1909. 



