THE PAEASITES OF POPILLIA JAPONICA 
The number of eggs present indicated that the attack was more than 
incidental. Observations were extended to the various sections 
north of Koiwai and to Hokkaido, the northern island. Here, at 
Sapporo, the proportion of beetles bearing these tachinid eggs 
approached 100 per cent. 
It was evident that this 
was a parasite capable of ex- 
erting a marked check upon 
PopiUia japonica, and that 
it might well be of equal value 
if introduced into America. 
Arrangements were at once 
made to study the species both 
at Koiwai and at Sapporo, 
to determine its life history, 
its method of parasitism, and 
other points in its biology 
which might prove of value 
in determining its relation to 
the host. Ways and means 
of breeding and handling were 
also sought in order that its 
importation into the United 
States in the living condition 
might be assured. These stud- 
ies were continued for some 
10 days, and a small number 
of parasitized beetles collected and confined in cages for observa- 
tion, when the sudden and unexpected disappearance of both the 
host and parasite at Sapporo, and of the latter only at Koiwai, 
Fig. 3.— Centeter cinerea, female 
Fig. 4. — Clumps of itadori (Polygonum reynoutria), a favoiite food plant of PopiUia japonica, 
Koiwai, Japan 
interrupted the work for the season. This was a development 
which was entirely unexpected, since the beetle itself had been 
present in numbers for not more than two weeks and it was 
