PKEVIOUS WORK WITH INSECT PARASITES. 23 



yet been reported upon, but theoretically speaking the experiment 



should have excellent results. 



|l 



THE TRANSFER OF BENEFICIAL INSECTS FROM ONE COUNTRY TO 



ANOTHER. 



Early Attempts. 



Dr. Asa Fitch, for many years State entomologist of New York, 

 was probably the first entomologist in America, or elsewhere for that 

 matter, to take into serious consideration the question of the transfer 

 of beneficial insects from one country to another. In 1854, following 

 a disastrous attack upon the wheat crop of the eastern United States 

 by the wheat midge (Contarinia tritici Kir by), a species that had been 

 accidentally introduced from Europe during the early part of that 

 century, Dr. Fitch, who had made a careful study of the insect both 

 in this country and from the European records, was struck with the 

 fact that in Europe the insect in ordinary seasons did no damage, and 

 that when occasionally it became so multiplied as to attract notice it 

 was but a transitory evil which subsided soon and was not heard of 

 again for a number of years. He was aware that in Europe certain 

 parasites of this insect were found, and, comparing the insects taken 

 from wheat in flower in France with those taken from wheat in flower 

 in New York, he found that in France the wheat midge constituted 

 but 7 per cent of the insects thus taken, while its parasites constituted 

 85 per cent; whereas in New York the wheat midge formed 59 per 

 cent of the insects thus captured, and there were no certain parasites. 

 He speculated as to the cause for this extraordinary difference and 

 wrote : 



There must be a cause for this remarkable difference. What can that cause be? 

 I can impute it to only one thing; we here are destitute of nature's appointed means 

 for repressing and subduing this insect. Those other insects which have been created 

 for the purpose of quelling this species and keeping it restrained within its appropriate 

 sphere have never yet reached our shores. We have received the evil without the 

 remedy. And thus the midge is able to multiply and nourish, to revel and riot, year 

 after year, without let or hindrance. This certainly would seem to be the principal if 

 not the sole cause why the career of this insect here is so very different from what it is 

 in the Old World. 



Quite naturally after this train of reasoning had entered his brain, 

 Dr. Fitch made an effort to introduce the European parasites of the 

 wheat midge, and in May, 1855, addressed a letter to John Curtis, 

 the famous English economic entomologist, and at that time president 

 of the Entomological Society of London, informing him of the immense 

 amount of damage done by the midge in America and suggesting the 

 manner in which parasitized larvae could be secured in England and 

 transmitted alive to this country. Mr. Curtis was ill and on the point 

 of starting for the Continent, but laid the letter before the Entomolog- 

 ical Society of London, which resulted in the adoption of a resolution 



