1908.] PUBLIC DOCUMENT- -No. 73. 177 



and the problem of caring for them is a serious one. They are con- 

 siderably parasitized by hymenopterous secondary parasites, so that it 

 will be necessary to keep them well protected, at the same time under 

 conditions as near the normal as possible. At the close of the fiscal year 

 between 6,000 and 7,000 puparia were already on hand. With one of the 

 smaller species of Tachinids breeding experiments were very successful, 

 and the species reproduced freely under these conditions, indicating that 

 it will be the part of economy to handle it in this manner, liberating 

 only after having bred large numbers. 



The large predatory beetles of the genus Calosoma, referred to in 

 previous reports, have been successfully introduced in considerable 

 numbers. Calosoma sycophanta was discovered in several of the field 

 colonies in the spring of 1907, having established itself, survived the 

 winter and reproduced. It is a valuable importation, but whether it 

 will prove in itself sufficient to reduce the numbers of the gypsy moth 

 and the brown-tail moth to an appreciable extent is undetermined. 



In the report for last year the writer drew particular attention to 

 two species of the genus Pteromalus, small parasites of the super-family 

 Chalcidoidea. Some 60,000 were reared in the early summer of 1906, 

 and the great majority of them were liberated. That the species has 

 established itself, at least temporarily, has been shown by the fact that 

 specimens were bred in the spring of 1907 from nests collected in 

 colonies of the year before. Throughout a considerable portion of the 

 territory directly north of Boston, within which all of the larger colonies 

 were planted last year, the caterpillars of the brown-tail moth died very 

 generally from a fungous disease, and as a result there was a scarcity 

 of the hibernating nests: therefore it was not considered desirable to 

 collect for breeding purposes many of these nests, and it is confidently 

 expected that the species will be found more abundantly in the col- 

 ' lections of nests made this winter. Several new colonies have been 

 planted in quite widely separated localities. 



The difficulty of determining the exact names of these European 

 parasites, nearly all of which are very common members of the European 

 fauna, is scarcely to be believed. The two species of Pteromalus, for 

 example, mentioned in the last report, have been a source of great 

 difficulty. The writer was unable to find them represented in the large 

 museums at Vienna, Dresden, Berlin, Brussels and London, nor did 

 they occur in the type collections of Ratzeburg at Eberswalde, where, 

 on account of that writer's important work on the parasites of Euro- 

 pean forest insects, one would naturally expect to find them. At last, 

 in the Museum of Natural Histoiy in the Jardin des Plantes at Paris, 

 specimens of both species were found that had been reared many years 

 ago by the French entomologist Sichel, and had been named for him by 

 the eminent authority on parasites, Arnold Foerster of Germany. They 

 will therefore in the future be known definitely as Pteromalus nidulans 

 .Foerst. and Pteromalus egrcgvus Foerst. 



