June 15, 1921 
Life-History Studies of Three Jointworm Parasites 413 
reared in Harmolita galls as a control on those reared in glass cells for the 
purpose of determining how well th<e glass cells approximated normal 
conditions for these parasites, for that particular season, showed that 
many larvae qf the first generation did not pupate during that season. 
This was found to be true likewise of Homoporus chalcidiphagus . 
PREPUPA 
The prepupal stage (PI. 77, A; fi£. 5) in three specimens observed 
varied from 1 to 6 days, with an average of 2 days. The larva does not 
void excrement during its earlier stages of development, but when the 
full-grown larva is ready to pupate, a considerable amount of excrement 
is voided and the specimen contracts considerably. The first four seg¬ 
ments of the abdomen contract equally until each is somewhat less than 
half its usual length in the full-grown larva. If the specimen is viewed 
from the ventral aspect, the last two segments of the abdomen appear 
Fig. 5. —Ditropinotus aureoviridis : Prepupal stage. X 34. 
to curve backward dorsally. The measurements of two prepupae aver¬ 
aged 2.2050 mm. in length and 0.9450 mm. in greatest width. 
PUPA 
Pupation was observed upon one occasion, the process requiring 17 
minutes. The fully developed pupa was plainly visible through the 
old larval skin, which first split down the center of the head, and the 
pupa then gradually worked itself forward through the opening. At 
first the pupa is a very delicate brown in color, gradually changing and 
becoming very dark, approximating the color of the adult insect. The 
pupal ?tage varies in length from 8 to 15 days. The average for 8 speci¬ 
mens observed in glass cells was 10 days. Six female pupse (PI. 77, C; 
fig. 6) averaged 3.0479 mm. in length and 0.8108 mm. in greatest width. 
Ope male pupa (PJ. 77, D;fig. 7) measured 2.66 mm. in length and 0.91 
njm. in greatest width. 
ADUI/T 
4 No males normally occur in the first generation of this species, and 
the females seem greatly to outnumber the males in succeeding genera¬ 
tions. They pass the winter as full-grown larvae in the gall-like cells 
42270°—21 - 4 
