BROWN-TAIL MOTH AND PARASITES IN EUROPE. 135 



numerous as to lay their eggs in quantities on growing nursery seed- 

 lings and low-growing plants. 



Among the very many lots 01 caterpillars and cocoons which have 

 been received at the laboratory there is occasionally one in which a 

 fungous disease is present. Usually, when it is present at all, the 

 majority of the caterpillars received from that particular locality 

 will be found dead and "shooting" the ascidiospores upon receipt. 

 According to Dr. Roland Thaxter, to whom specimens have several 

 times been submitted, it is specifically identical with the fungus 

 which is so effective in America as to have largely assisted in reduc- 

 ing the moth from the preeminent place which it would otherwise 

 have occupied as a pest. Its presence under these conditions, as it 

 was, for example, in 1909, in practically every box out of a large 

 number which were forwarded to the laboratory from lower Austria, 

 is strongly indicative of the importance of this disease. 



Looked at from one standpoint, the brown-tail moth situation in 

 America is less satisfactory than is the gipsy-moth situation. In 

 numerous localities throughout western Europe as well as in eastern 

 Europe it frequently increases to such an extent as to become a 

 pest. It hardly seems as though more could be expected of the 

 European parasites in America than is accomplished by them in 

 Europe, but if even this much can be secured it will aid materially 

 in reducing the frequency of the outbreaks. At the same time, it must 

 be admitted that from nearly every point of view the prospects of 

 unqualified success with the gipsy-moth parasites are better than 

 with the parasites of the brown-tail moth. 



SEQUENCE OF PARASITES OF THE BROWN-TAIL MOTH IN EUROPE. 



The accompanying table (Table III), in which are listed all of the 

 parasites of the brown-tail moth which have been definitely asso- 

 ciated with that host in the course of the studies of imported Euro- 

 pean material, is constructed in the same manner as the tables of 

 parasites of the gipsy moth in Japan and in Europe (see pp. 121, 132). 

 It will be noted that the number and variety are slightly larger than of 

 European gipsy-moth parasites, and that the species which are or 

 which appear to be promising as subjects for attempted importation 

 are also slightly more numerous. Very rarely, however, does any 

 one among them become as relatively important as any one* of 

 several among the gipsy-moth parasites which might be mentioned. 

 Neither has any lot of brown-tail material produced so many para- 

 sites of all species (as high a percentage of parasitism) as have several 

 lots of gipsy-moth material. 



