166 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 
to be concluded in considerably less than one week after the spinning 
of the cocoon if the weather is hot, and ever. under the best of con- 
ditions which can be devised for keeping them alive the mortality is 
heavy. Even in the ordinary temperature of a steamship’s cold 
room development continues. 
TACHINID PUPARIA. 
The importation of tachinid puparia is by no means so simple as 
the importation of Apanteles cocoons, but at the same time it is easy 
as compared with the difficulties attending the importation of live 
eipsy-moth caterpillars from which to rear these puparia in America. 
In all, quite large numbers have been received from both Europe 
and Japan. A variety of methods has been tested in the hope of hit- 
ting upon one that would be applicable for the purpose. Shipping 
in damp earth was early attempted, and seems to be the very first 
method which suggests itself to anyone wishing to ship a quantity 
of them, but of all ways it is very nearly the worst. It would prob- 
ably be the best, if the larve could be allowed to enter the earth 
naturally and if they were left there wholly undisturbed throughout 
the time they were in transit, but mingled with damp earth and 
placed in a box to be sent by mail or express, disaster is pretty sure 
to result. Cotton has also been used several times, and it is usually 
as bad and sometimes worse. With the exception of excelsior, cot- 
ton is about the worst packing for living insects that has come under 
observation at the laboratory, although gritty moss, of a sort which 
dries brittle, is also bad. Presumably there are other worse sub- 
stances, but they have not been discovered at first hand. 
Probably the best packing material is slightly damp and preferably 
living sphagnum moss. The live moss retains its moisture in a man- 
ner wholly different from the moss which has been killed, dried, and 
subsequently dampened. Test shipments, which were sent to France 
and back without being opened, returned to the laboratory in good 
and almost unaltered condition, in the case of those which were 
inclosed in tight boxes. Even when fully exposed to the air the liv- 
ing moss seems to dry much more slowly and to hold its moisture 
more naturally. Sphagnum possesses the great additional advan- 
tage of being much softer when dry than most other kinds of moss. 
One disadvantage attending the shipment of puparia, no matter 
how they are packed, is that of secondary parasites. A single colony 
of Dibrachys, issuing en route from one of a lot of puparia, will result 
in the parasitism of a large proportion of the remainder. This 
might possibly be prevented by packing in sand or earth, but this 
appears to be about the only advantage possessed by that method. 
The puparia of certain tachinids must be kept damp, but this is not 
at all necessary in the case of all. Methods of packing and shipment 
