28 BULLETIN 1429, U. S. DEPARTMENT OF AGRICULTURE 
Alternation of hosts 
The parasite larvae of the second stage, which carry the species 
over the winter, are found in three host species, Miridiba Jcoreana 
N. and K., Popillia castanoptera, and Phyllopertha sp. An examina- 
tion of field-collected grubs on October 10 revealed the following 
condition: Anomala spp., all Dexia larvae either dead or lost in 
molting; Phyllophaga spp., all Dexia larvae either dead or lost in 
molting; Miridiba koreana, all Dexia larvae in second stage, healthy; 
Phyllopertha sp., all Dexia larvae in second stage, healthy; Popillia 
castanoptera, all Dexia larvae in second stage, healthy;. Popillia 
atrocoerulea, all Dexia larvae dead. 
The three species which contained living parasite larvae at this 
time naturally included the true host. Popillia castanoptera may 
be excluded, since its time of pupation is too late for this generation 
of parasites. Although it can not be stated as yet with certainty, 
the available data indicate that Miridiba Jcoreana is the major if not 
the only host of the overwintering generation. 
The host of the following generation is also not positively known, 
but a consideration of the species of beetles of proper size pupating 
about midsummer points to Popillia castanoptera and P. mutans as 
the more probable species. 
The third generation of adults emerges exclusively fhrai larvae 
of Serica, which latter pupate late in the fall and pass the winter 
in the adult form in the soil. An examination of field-collected 
grubs obtained August 12 to 27, 1923, gave the following data: 
Number 
exam- 
ined 
Number ' F ^' 
Wgf- ! pSl 
lzea 1 ism 
Anomala spp. (third stage) - - .-. .-. -- .-. .-. 
3,647 
8,545 
935 
51 1.4 
Phyllophaga spp. (second stage) -._ -. 
863 l 10. 1 
Serica spp. (third stage) . - - . - - 
129 13.8 
Popillia spp. (third stage) -.- ... - - - .. 
137 

The counts of parasitized grubs were based upon the funnels 
visible through the derm, and consequently a portion of the parasites 
may have been dead at the time of collection without this fact being 
noticed. Dissections of a representative series were made and the 
living Dexia larvae found to be in the second stage, though those in 
Serica seemed to be further advanced, and a few had attained the 
third stage. All the remaining parasitized grubs were set aside in 
trays for development and were again examined on August 27. 
Of the 863 Phyllophaga grubs, 747 were still in the second stage, 
and dissections showed all parasite larvae contained in them to have 
been killed in the first or early second stage, whereas 116 grubs had 
transformed to the final stage and had rid themselves of all evidence 
of parasitism in the process. Among the Serica grubs 82 were still 
alive and contained third-stage Dexia larvae, whereas 37 had already 
died and yielded puparia. 
Rare instances have been observed of this species reaching ma- 
turity in field-collected pupae. In one instance a Serica grub con- 
taining a late second-stage larva was able successfully to pupate 
