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 cf 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 ‘‘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,! and 
was partly republished in English in the Popular Science Monthly in 
1908.2. Theother, by Prof. F. Silvestri, of the Royal Agricultural School 
at Portici, Italy, entitled ‘‘Consideration of 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 Jtahan 
Agriculture,’’ was published in 1909.” 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 larvee 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 
specics born from the same pupa. A later writer, Vallisnieri (1661— 
1 Annals of the National Agronomical Institute (Superior School of Agriculture), second series vol. 6, no. 
2, Ep. 281-354, Paris, 1907. 
2 Popular Science Monthly, vol. 72, pp. 353-370, 407-419, April and May, 1908. 
3 Bulietin of the Society of Italian Agriculturists, vol. 14, no. 8, pp. 305-3867, Apr. 30, 1909. 
