June is, 1921 
Life-History Studies of Three Jointworm Parasites 419 
PREPUPA 
The prepupal stage (PL 74, C; fig. 12) of the larva is indicated by the 
contraction of the anterior abdominal region, the greatest constriction 
occurring in the first 2 abdominal segments which contract to about 
one-half the original width. In this 
stage a large amount of excrement 
is voided and the prepupa is then 
pure white in color. No excrement 
is voided during any period of larval 
growth. Observations on 37 indi¬ 
viduals showed that they remained 
in this stage from 1 to 6 days, the 
average length of three prepupae was 
averaged 0.8633 mm * 
Fig. 12. —Homoporus chalcidiphagus: Ventral 
view of prepupa. X 20. 
average being about 2 days. The 
2.4966 mm. and the greatest width 
PUPA 
The pupa (Pi. 74, E-G) of this species is at first pure white. The eyes 
first begin to turn pink and gradually grow darker as the remaining 
portions of the body become dark. The entire pupa finally becomes 
bluish black, approximating the color of the adult. The length of the 
pupa stage was found to vary from 5 to 23 days for individuals pupating 
during the same breeding season. The average length of the pupal 
period for 64 individuals was between 9 and 10 days. The average 
length of 3 female pupae was 3.5 mm. and the greatest width averaged 
0.7933 mm * ’> the average length for 3 male pupae was 2.7533 mm -1 an d the 
greatest width averaged 0.7933 mm - The male pupa can easily be 
distinguished from the female pupa by the fact that the antennae extend 
the full length of the tarsi of the forelegs. This is not true of the 
female pupa. 
ADULT 
The adult (fig. 8) emerges in Virginia during the latter part of May 
and continues breeding up into the month of October. Even in the 
northern States on warm days in October this parasite has been observed 
in the fields. Five complete generations were reared at this laboratory 
in cell slides from May to September in 1918. These observations 
accorded wdth rearings in Harmolita galls in wheat stems kept under 
similar conditions. 
Males normally occur in about equal numbers with females, though 
this species will breed parthenogenetically, in which case the offspring 
are males. 
The average number of eggs deposited for 5 individual females was 
31.8, for an average period of 15.2 days. One individual deposited 45 
eggs during a period of 17 days. One individual lived for 31 days. The 
