20 IMPORTED PARASITES. 



PARASITES OF THE GYPSY MOTH IN AMERICA. 



There is just one parasite of the gypsy moth in America, na- 

 tive to the country, which rauks in importance with the least 

 of those included in the tables of Japanese and European para- 

 sites. This is Theronia, and the native species is so similar in 

 habit as to be indistinguishable from the other species of the 

 same genus which attack the same host in Europe and Japan, 

 and it cannot as yet be stated with assurance that it is not the 

 same. It is literally the least important of all of the parasites 

 listed, and the maximum effectiveness in America is, if any- 

 thing, less than in any foreign country. It cannot be credited 

 with destroying more than 1 in 30 or 1 in 50 of the pupae, on 

 the average, and never more than 1 in 10 under the most fa- 

 vorable conditions ever observed. A table of the native para- 

 sites of the gypsy moth (leaving out the rare and inconsequen- 

 tial species), prepared for comparison with those of the Euro- 

 pean and Japanese, would consist of this species and no other, 

 and the difference is obvious. 



In Table 3 are listed all of the parasites which have been 

 received from Europe or Japan in sufficient numbers to make 

 possible satisfactory colonization in America. There are 4 or 5 

 more which have been liberated in small numbers, or which are 

 on hand ready for liberation in the spring, including Tachina 

 japonica and Chalcis ohscurata, Japanese representatives of the 

 European species, and having nearly identical habits. There 

 are also on hand at the laboratory a large number of the hiber- 

 nating puparia of Parasetigena segregata and Crossocosmia sp., 

 both of which are parasites of some promise, and neither of 

 which has yet been colonized. 



