PAEASITES OF LARGER BROWN-TAIL CATERPILLARS. 295 



than the brown-tail moth, and its rate of multiplication, being un- 

 questionably more rapid than that of the brown-tail moth, ought not 

 to be checked until it has become a factor in the control of its own 

 particular host. 



It may be added as a postscript that a few days after writing the 

 above a few hundred caterpillars of the brown-tail moth collected in 

 the field from hibernating nests were dissected in the laboratory. In 

 them were found several of the characteristic first-stage Zygobothria 

 larvae (fig. 63, p. 264) embedded in the walls of the gullet. The evi- 

 dence presented by this small number of dissections is less satisfactory 

 than though the number were larger, but if it is to be accepted the 

 rate of increase of Zygobothria in 1910 is considerably better than was 

 expected. 



PARASITES ATTACKING THE LARGER CATERPILLARS OF THE 



BROWN-TAIL MOTH. 



HYMENOPTEROUS PARASITES. 



In Europe after the caterpillars of the brown-tail moth resume 

 activity in the spring they become subject to attack by a variety of 

 tachinid parasites, but so far as has been determined by rearing work 

 with imported material the only hymenopterous parasite of any con- 

 sequence is Meteorus, which passes the winter as a first-stage larva in 

 the hibernating caterpillars. 



In fact, only a single other parasite has ever been reared from 

 imported caterpillars which may not have come from some other acci- 

 dentally included host, and this is the Limnerium disparis, which has 

 already received attention as a minor parasite of the gipsy moth. It 

 would certainly seem as though there were likely to be others attack- 

 ing the caterpillars of the brown-tail moth in Europe in spite of the 

 fact that none has been secured, and this supposition is upheld by the 

 published results of a study in the parasites of the brown-tail moth 

 which was made a few years ago by a Russian entomologist, Mr. T. W. 

 Emelyanoff . He mentions a number of parasites which have not been 

 reared at the laboratory from imported material, and among them one, 

 Apanteles vitripennis Hal., which is so common, according to his ac- 

 count, that the "cocoons are sometimes accumulated together in great 

 numbers." Any suspicions that the Apanteles thus observed by him 

 is identical with A. lacteicolor Vier, as reared at the laboratory and 

 which is the only representative of the genus that has been reared 

 from caterpillars collected in Russia or elsewhere, is at once dispelled 

 by his detailed account of the early life and habits of the species which 

 he had under observation and which differ in all essential par- 

 ticulars from the life and habits of A. lacteicolor. The caterpillars 

 are attacked soon after they leave the nests. Instead of dying in 



