1906.] PUBLIC DOCUMENT No. 73. 135 



1. To collect in Europe a large quantity of parasites and 

 parasitized nests, caterpillars and pupte of the moths. 



2. To pack safely and ship them so that they may arrive 

 with the least possible delay. 



3. To care for the material in such a way that as many 

 parasites as possible may be obtained. 



4. Most important of all, to detect and kill every single 

 form of injurious secondary parasites. 



5. To propagate the true parasites under the most favor- 

 able conditions. 



6. To finally liberate large numbers of these parasites in 

 close proximity to the caterpillars which are their natural 

 hosts. 



Thus it will be seen that this important work of importing 

 parasites involves a considerable amount of time, as well as 

 painstaking care and the highest technical skill. It cannot 

 be done in a year, nor probably even in two years. It cannot 

 be done by amateurs ; it must be done by specialists, work- 

 ing carefully, working slowly, it may be, and taking every 

 possible precaution to prevent failure. No better illustra- 

 tion of how dangerous a thing " a little knowledge " may be 

 can be found than in the flippancy and positiveuess with 

 which certain newspaper writers and men well trained in 

 other lines but with hardly a smattering of entomological 

 knowledge discuss this matter and advise how best to pro- 

 ceed. Laymen who would not attempt to advise how to 

 treat a case of pneumonia or interpret a doubtful point of 

 law, are prompt to dictate the course to be followed in one 

 of the most technical and difficult problems in the whole 

 field of entomology. 



The practical question for the taxpayer is whether the 

 $10,000 appropriation per year for three years now avail- 

 able will yield tangible results, or not. To answer this 

 would involve omniscience. The superintendent is hope- 

 ful, even sanguine, that in the end the importation of the 

 natural enemies of the moth from abroad may solve suc- 

 cessfully the great problem in which we are now en- 

 gaged. But nature cannot be reduced to a mathematical 

 basis. She is full of surprises. Promising lines of re- 



