GYPSY AND BROWN-TAIL MOTHS. 



51 



in so many particulars, however, as to make such an estimate 

 at the present time largely speculative. 



In Table 4 are listed all of the parasites of the gypsy moth 

 which have been liberated in America under conditions in every 

 way satisfactory. The dates when the first satisfactory colony of 

 each was established will be found in the second column. When, 

 as so frequently happened, the parasite was secured too late in 

 the season to make its attack upon the caterpillars possible until 

 another year, the circumstance is indicated in the third column. 

 The fourth column indicates when the parasite was first recov- 

 ered from the immediate vicinity, and the fifth when it was 

 found to be generally distributed. On the supposition that the 

 progress of the parasites later liberated will be comparable with 

 that of the earlier, the dates when each of the species listed can 

 be expected to become effective in their respective roles of egg, 

 caterpillar or pupa parasites, are indicated in the last column. 



Table 4. — Showing Date of Liberation and Subsequent Progress of the 

 Parasites of the Gypsy Moth in Massachusetts. 



1 A native parasite, of slight relative importance. 



2 First recovered at a distance from colony. 



3 jvdults indistinguishable from a native species, which is rarely parasitic on the gypsy moth. 



4 It is not known positively when Tricholyga was first liberated, owing to its very close re- 

 semblance, in appearance of adult, to Tachina. The recovery from the field in 1909 may have 

 been the result of colonization in 1908 j or equally well of that of earlier years. 



