IMPORTATION AND HANDLING OF PARASITE MATERIAL. 159 
possible. The remainder were placed in small tube cages, and taken 
to the field where they were to be liberated. An attendant counted 
the number of flies issuing, and watched for secondary parasites. 
Since no secondary parasites issued in the summer from puparia 
secured in this manner, in 1910 the puparia were merely placed in 
cages which were taken to the colony site and left unattended until 
the flies had ceased to issue. 
After the adults of the summer-issuing forms have all ceased to 
emerge, the sound puparia are more or less carefully sorted. Those 
supposed to be Parasetigena segregata, indistinguishable externally 
from dead Tricholyga or Tachina, are buried in damp earth for the 
winter. Mr. J. D. Tothill, one of the assistants at the laboratory, 
devised an ingenious method for separating the puparia containing 
the healthy pupe of Parasetigena from those containing dead Tachina 
or Tricholyga, by holding them so that they were viewed against a 
narrow beam of very strong light. The method was not infallible, 
but served its purpose fairly well, and was the first of many which 
had been experimented with which was at all successful. 
The living caterpillars removed from the boxes have been placed 
in cages or trays and fed, but only an insignificant proportion of them 
has ever lived long enough to be killed by the parasites which many 
of them have contained. Large numbers of them have been dissected 
for the purpose of determining the proportions parasitized. 
The dead caterpillars not infrequently contain the puparia of 
Tricholyga, when this parasite happens to be common in the locality 
from which the shipment originated: Under such circumstances 
they are placed in tube cages for the emergence of the flies. If 
Tricholyga is not present in the boxes in the form of free puparia the 
dead caterpillars may as well be discarded, since it is only very 
rarely that any other tachinid pupates in this manner. 
Pupex, both living and dead, nearly always contain a considerable 
number of the larve of Blepharipa scutellata. They are, therefore, 
placed over damp earth in order that the larvae may pupate under 
natural conditions. Other tachinids may occur in the pupa, but 
never in anything but insignificant numbers. 
GEPST-MOTEH, PUPA. 
It would seem as though it ought to be an easy matter to import 
the pupz (Pl. VI) of the gipsy moth in good condition, but for 
reasons which are not altogether clear in every instance the vast 
majority of the importations of pupx have been worthless, or worse 
than worthless, since the handling of worthless material involves an 
additional waste of labor. Too often the cause of failure is directly 
and obviously the result of careless packing, and the number of lots 
of pupx which have been received packed with the care which is 
