THE PAEASITES OF POPILLIA JAPONIC A 
11 
were engaged in collecting at one time. They were shown speci- 
mens of the beetle bearing eggs of Centeter cinerea and offered 50 
sen (25 cents) per hundred for all brought in. In this way as many 
as 56,000 were secured in a single day during 1922. Since the beetle 
is killed within six days after the deposition of the egg it was evi- 
dent that the feeding period of the host itself was very short, and 
consequently elaborate arrangements for providing food in the cages 
were not necessary. Cardboard boxes of about one-third cubic foot 
capacity were used, each being filled loosely with grape or Polygonum 
foliage, and from 500 to 1,000 beetles were placed therein. These boxes 
were set aside without further attention for six days, after whicj^i they 
were opened and the beetles still alive were permitted to escape, as 
the parasites of these had died without effecting the death of the 
Fig. 10. — Spalangia sp., a parasite of Centeter cinerea 
host. Had these beetles been permitted to die in the boxes their 
putrefying bodies would have exerted a detrimental effect on the 
larvae and puparia present. It was found that the foliage in the boxes 
maintained a fairly high moisture content for a considerable period, 
so that pupation was effected without difficulty. Upon the com- 
pletion of this the dead beetles containing the puparia were screened 
out and packed in moderately moist sphagnum moss for shipment to 
America. 
From the shipments thus far made a large number of adults 
have been obtained. In 1922, however, only 700 adult flies were 
reared at the Riverton laboratory, but in 1923 approximately 7,000 
were secured. These were liberated in the field, and beetles bearing 
Centeter eggs were found one week later. This colony survived the 
winter in good condition, for in the summer of 1924 beetles bearing 
eggs were found 2 miles from the point of the previous year's libera- 
tion, or covering an area of approximately 12 square miles. 
