340 
Journal of Agricultural Research 
Vol. VII, No. 7 
Third instar. —Morphological characters. Antennae with the following measure¬ 
ments. Segment III, 0.192 to 0.224 mm., average 0.206 mm.; IV, 0.088 to 0.104 mm., 
average 0.096 mm.; V, (0.064 plus 0.264 mm.) to (0.072 plus 0.296 mm.), average (0.065 
plus 0.273 mm.). Cornicles 0.112 mm. 
Color characters: Somewhat more orange-yellow than the earlier instars, with more 
or less distinct brownish areas about the bases of the cornicles. 
Fourth instar. —Morphological characters. Antennae with the following measure¬ 
ments. Segment III, 0.144 to 0.184 mm., average 0.169 mm.; IV, 0.112 to 0.144 mm., 
average0.128mm.; V, 0.112 to 0.128mm., average0.12 mm.; VI, (0.064plus0.296mm.) 
to (0.08 plus 0.344 mm.), average (0.075 phis 0 -3 r mm.). Cornicles 0.144 mm. 
Color characters: General color yellow-orange, with brownish red patches around the 
bases of the cornicles; head grayish, eyes brown to black. 
Fifth instar, adult (PI. 22, B).—Morphological characters. Antennae with the 
following measurements: Segment III, 0.208 to 0.256 mm., average 0.241 mm.; IV, 
0.152 to 0.192 mm., average 0.169 mm.; V, 0.128 to 0.16 mm., average 0.142 mm.; VI, 
(0.08 plus 0.304 mm.) to (0.088 plus 0.36 mm.), average (0.081 plus 0.329 mm.). 
Cornicles 0.192 to 0.216, average 0.204 mm. Antennae without sensoria. Head 
occasionally with a pair of tubercles above but the last two segments of the abdomen 
without such tubercles. Cauda short and abruptly conical. 
Color characters: Similar to those given for the previous instar excepting that the 
colors are a little more distinct. The eggs show through the body as dark areas. 
Location: Found on the underside of the apple leaves feeding, or on the twigs or in 
the axils of the buds depositing eggs. 
nymphal stages 
The oviparous females required a period of from 20 to about 28 days 
for the immature stages. As with the males, the duration of the various 
instars varied greatly with the individuals, the principal cause of this 
being the variation of the prevailing temperatures. 
MATING 
Mating occurred mostly on the twigs. Males mated with several 
females and in some cases the oviparous females mated at least twice. 
As was the case with A . avenae , the male endeavors to copulate with 
every adult oviparous female he meets; and unless the female has just 
mated, she does not endeavor to hinder the male. 
OVIPOSITION 
Nineteen ovipara laid a total of 120 eggs, an average of 6.3 eggs per 
insect. Five of these oviparous females laid 36 eggs, an average of a 
little over 7 eggs each. The highest record for one oviparous female is, 
therefore, 8 eggs. 
FEEDING HABITS 
The results of the feeding of the rosy aphis are very noticeable, as the 
leaves are much curled thereby. (Pi. 24, B.) The young stem mothers 
crowd into the opening buds, and as the leaves grow they curl and twist 
about the insects. As young are produced these reach other leaves and 
