THE PARASITES OE POPILLIA JAPONICA 
37 
Three additional molts occur before the final larval stage is reached, 
and at each one the head is shifted forward and a new feeding punc- 
ture made. The successive cast skins remain in a leaflike form as a 
pad beneath the body, serving to attach the parasite larva to the host 
during these stages. There is thus a total of five larval stages, with 
the eggshell and four cast skins adhering to the final stage. This is 
shown diagrammatically in Figure 27. 
In the last stage feeding js continued at the puncture hole until 
after the death of the host, when suctorial action no longer suffices 
and the mandibles are brought into use. The entire body of the host, 
exclusive of the head and a portion of the legs, is ordinarily consumed, 
as well as the cast skins of the parasite itself. 
The presence of the egg or early-stage larva on the body causes no 
appreciable inconvenience to the host grub, but as feeding advances 
it becomes weakened through withdrawal of the body fluids. Death 
of the host occurs when the parasite larva is in the fifth instar and the 
formation of the cocoon of 
the latter takes place with- 
in about two days. The 
duration of the larval stages 
varies considerably with the 
temperature conditions, 
and ranges from 14 days 
under high temperatures at 
Yokohama to nearly a 
month at Koiwai. 
Following the completion 
of feeding, the spinning of 
the cocoon is* immediately 
begun, and this takes place 
in situ in the soil cell of the 
host. The outer covering is of very loose texture, but the succeeding 
ones are much more compact. The inner surface is very smooth and 
firm. The meconium of the larva is cast immediately after the 
completion of spinning and remains as a hard pad at the posterior end. 
The dormant period is passed in the larval stage within the cocoon, 
and pupation occurs only a short time prior to the appearance of the 
adult. 
The first adults appear in the field between August 14 and 18, 
reaching a maximum abundance near the end of the month and 
disappearing by the middle of September. The period of gestation 
covers several days to one week, and, consequently, only about two 
weeks are available for extensive breeding work. The wasps appear 
on bright days about 10 a. m., the males slightly earlier, and feeding 
continues until noon. On cool, cloudy days they are present through- 
out the day, having been observed feeding as late as 6 p. m. 
During 1920 feeding by the adults was confined largely to the 
blossoms and to the nectar glands on the leaf petioles of itadori 
(Polygonum reynoutria), but in the two years following was almost 
entirely at the blossoms of two umbelliferous plants, Seseli libanotis 
and Patrinia scdbiosaefolia. After feeding for the day is complete 
the females return to the breeding grounds, and there search out 
Fig. 27. — Diagrammatic representation of the position of 
the successive larval stages of Tiphia in situ upon the 
host, showing the mouth parts remaining in the old 
feeding punctures. Largest outline represents the fifth 
and last larval stage 
