336 
Journal of Agricultural Research 
Vol. VII, No. 7 
V, 0.192 to 0.256 mm., average 0.225 mm -; VI, (0.088 plus 0.368 mm.) to (0.112 plus 
0.512 mm.), average (0.097 to 0.441 mm.); segments imbricated, armed with a few 
hairs, but without sensoria. Antennal tubercles distinct; head without dorsal tuber¬ 
cles met with in the wingless form from apple. Legs slender; hind tibia 0.656 to o.784 
mm. long. Cornicles very slender, slightly curved, distinctly flanged and imbricated; 
length, 0.384 to 0.464 mm., average 0.443 mm - Abdomen without the prominent 
caudal tubercles met with in the apple form; cauda conical, rather elongate, more 
slender than that of the apple form, armed with three pairs of hairs and imbricated 
by rows of minute setae. Form more elongate than the spring wingless forms, 1.36 by 
0.8 mm. 
Color characters: Color creamy-yellow with a slight brownish or even purplish cast; 
eyes dark brown; distal portions of antennae, tips of cornicles, tip of labium, and 
tarsi brown or dusky. Between the cornicles and inclosing their insertions is a band 
of rusty red, this color sometimes also extending into the proximal portion of the cor¬ 
nicles; the red eyes of the embryos showing through the abdomen of the adult. 
Location: Found in colonies on the under surface of the leaves of rib grass (Plantago 
lanceolate) and also on the flower stems; rarely also on other species of the genus. 
DURATION OR NYMPHAL STAGES 
This form of the species became adult in from 8 to 12 days, the period 
varying with the prevailing temperature. Insects born from the 10th 
to the 20th of June required 10 days for this period, while those bom in 
July matured in 8 to 9 days. Later the period increased again to 12 
days in September. 
REPRODUCTION 
The average number of young produced by 35 adults was 65.2, the 
maximum being 108 (produced by two insects) and the minimum 12. 
The average length of the reproductive period was 19 days, thus varying 
from 5 to 35 days. The average daily production of these 35 adults 
was 3.4 young per mother. The greatest average daily production for 
one adult was 5.4, this insect producing 43 young in 8 days; the lowest 
was 2.2, 77 young in 35 days. One insect brought forth 14 young in one 
day while 8 produced 10 or more in a like period. Of the two winged 
insects which reproduced, one brought forth 21 young in 7 days, and the 
other 13 young in 3 days. The first of the two lived for a few days after 
reproduction ceased. 
longevity 
• 
The average total length of life for this form was 28 days, varying 
from 14 to 45 days. In general the insects bom during the early part 
of the summer, particularly in June, were longer lived than any which 
followed, the latter all equaling or exceeding the average for the entire 
summer. 
SUMMER WINGED VIVIPAROUS FEMALE 
The early instars of this form are very similar to those of the summer 
wingless viviparous female and those of the fall migrant. A description 
of the fifth instar (adult) only will be given here. Since the form was 
