286 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



her to select certain hosts in preference to certain others, as in the 

 instance of the American and European races of Parexorista chelonise. 

 Again, it may be in the ability of the young larvae to complete their 

 development upon a certain host, as in the case of Tachina mella and 

 Tachina larvarum. Or again, it may be that the difference lies as be- 

 tween Apanteles lacteicolor Vier. and A. conspersse Fiske in the methods 

 of attacking the host. 



As has already been recounted, no less than 45,000 adults of 

 Apanteles lacteicolor Vier. have been reared at the laboratory and lib- 

 erated in the field. In addition a very large number has been reared 

 under close observation during the winter or spring, and there has 

 been a large number of more or less successful reproduction experi- 

 ments conducted, in most instances with great care. In all this time 

 there has not been a single exception to the rule, that the larva of 

 Apanteles lacteicolor Vier. is solitary, and kills its host before issuing 

 from its body. Nothing whatever, either in the field, or in the many 

 experiments in reproduction, or in the occurrence of the parasite in 

 shipments of larger caterpillars from Europe, has indicated in any 

 way that it may ever attack the large caterpillars successfully, or 

 that it is ever anything else than solitary. 



Had Apanteles conspersse Fiske been received as a parasite of the 

 Japanese brown-tail moth without other data than the mere rearing 

 record it would undoubtedly have been considered as identical with 

 Apanteles lacteicolor Vier., but it is impossible so to consider it in view 

 of the fact that it is not solitary but gregarious; that it attacks, not 

 the small but the large caterpillars, and, if appearances of the material 

 from Mr. Kuwana were not deceiving, that the host is left alive instead 

 of being killed before the emergence of the parasite larva. These 

 differences are, or ought to be, sufficient to make of it another species. 



It is not at all improbable that if it were given the opportunity it 

 would attack the caterpillars of the European brown-tail moth, and it is 

 hoped that enough can be collected in Japan and forwarded to Amer- 

 ica to make the experiment possible. 



METEORUS VERSICOLOR WESM. 



A very few specimens of this parasite were imported in 1906 with 

 caterpillars of the brown-tail moth and the gipsy moth from several 

 European localities. In 1907, as already stated in the account of 

 Apanteles lacteicolor Vier., a few specimens of Meteorus (fig. 68) were 

 reared from caterpillars imported in hibernating nests the winter be- 

 fore. There were very few, less than 100 all told, and not enough to 

 colonize with any likelihood of success. It was therefore decided to 

 use them in a series of reproduction experiments, on the chance that 

 a much larger number might be reared for colonization. 





