THE PARASITES OF POPILLIA JAPONICA 
25 
At Sapporo the pupation of the earlier individuals begins about 
the first of July and ranges over the entire month. Under high tem- 
perature conditions the pupal stage averages about 22 days, whereas 
at Sapporo it may extend to 30 days in case the weather is cool. 
Emergence occurs during the early morning hours. 
HABITS OF THE ADULT 
The adults are somewhat crepuscular in habit, being active on 
bright days largely about sunset, but at Koiwai the greatest num- 
bers were always to be found during the rainy periods which occurred 
almost daily, and practically all collections were made under these 
conditions. Heavy rains, however, caused them to remain quiescent 
on the under sides of surrounding foliage. Feeding takes place 
largely at the blossoms of two umbelliferous plants (Seseli libanotis 
and Patrinia scabiosaefolia) . 
A , jlX -'J'!. 1 .',^'-". 1 ■" '-'' ■■■'■■.' ■ '." 
Fig. 21.— A, larva of Prosena siberita in situ, with tracheal funnel attached to trachea of 
host; B, tracheal funnel of Dexia ventralis penetrating the derm of host 
Mating is effected largely upon the blossoms of these food plants 
or upon surrounding f oh age and at times upon tree trunks. The 
pairs may remain in copula for a considerable period, and at this 
time may be captured very readily. Single individuals are very 
active and take alarm quickly. 
CHARACTERS FOR DETERMINING THE IMMATURE STAGES OF PROSENA SIBERITA 
First-stage larva (fig. 20, F) . — Length of newly hatched larva approximate^ 
1 mm.; color white. Mouth hooks present; pharyngeal plates as in G. Sensory 
papillae prominent. Derm finely striate. Body segments each bearing a strong 
lateral bristle; caudal setse four in number. Posterior spiracles sessile. 
Third-stage larva (fig. 21, A). — Length 14 mm.; color white. Caudal spiracles 
as in Figure 20, I. Tracheal funnel always attached internally to the large 
tracheal trunk of the host near the thoracic or first abdominal spiracles. 
Pwparium (fig. 14, B). — Length 10 to 12 mm.; color dark brown, reflections 
dull, surface striate. Posterior spiracles divided into three lobes bearing the 
branchlike design of the former tracheal openings; thoracic spiracle present in 
the form of an elevated tube. 
98689—27 4 
