Nov. 13, 1916 
Rosy Apple Aphis 
* 329 
with the proximal half pale yellow and the distal half dusky or black. Labium pale 
yellow tipped with dusky brown; body somewhat pulverulent. 
Second instar. —Morphological characters. Antennae with the following measure¬ 
ments: Segment III, 0.192 to 0.232 mm., average 0.212 mm.; IV, 0.096 to 0.112 mm., 
average0.104nun.; V, (0.064 plus 0.256 mm.) to (0.08 plus 0.288 mm.), average (0.067 
plus 0.272 mm.). Cornicles about 0.112 mm. 
Color characters: Somewhat similar in color to the insects of the first instar, but 
somewhat more pinkish as compared to the distinct yellow of the first instar. 
Third instar. —Morphological characters. Antennae with the following measure¬ 
ments: Segment III, 0.208 to 0.24 mm., average 0.22 mm.; IV, 0.160 to 0.192 mm., 
average 0.177 mm.; V, 0.128 to 0.150 mm., average 0.14 mm.; VI, (0.064 plus 0.288 
mm.) to (0.088 plus 0.384 mm.), average (0.083 plus 0.342 mm.). Cornicles 0.176 to 
0.224 mm., average 0.198 mm. 
Color characters: Much darker than the earlier instars, taking on the rosy tint of the 
adult insects and the gray slaty powdering met with on the adult. 
Fourth instar. —Morphological characters. Antennae as follows: Segment III, 
0.304 to 0.4 mm., average 0.352 mm.; IV, 0.208 to 0.328 mm., average 0.271 mm.; V, 
0.144 to 0.208 mm., average 0.187 mm.; VI, (0.08 plus 0.352 mm.) to (0.102 plus 0.504 
mm.), average (0.094 plus 0.433 mm-)* Cornicles 0.24 to 0.288 mm., average 
0.259 mm. 
Color characters: Similar to the previous instar, although darker and more nearly 
like the adult.. 
Fifth instar (adult) (PI. 21, C).—Morphological characters. Antennae with the 
following measurements: Segment III, 0.43 to 0.656 mm., average 0.52 mm.; IV, 
0.256 to 0.48 mm., average 0.348 mm.; V, 0.192 to 0.288 mm., average 0.235 mm.; 
VI, (0.096 plus 0.4 mm.) to (0.128 plus 0.592 mm.), average (0.108 plus 0.486 mm.). 
Cornicles 0.336 to 0.496 mm. Body rotund; upper surface of the head often with two 
rather prominent tubercles and a similar pair on the dorsum of the last two abdominal 
segments. Cauda short, abruptly conical, setose, cornicles distinctly flanged and 
slightly curved, imbricated. Antennae not distinctly imbricated, except the distal 
segments. Labium extending to between the second and third pairs of coxae. Lateral 
tubercles distinct. 
Color characters: General color rosy brown, having a pinkish cast, owing to a 
powdery covering. Some of the older specimens are almost of a purplish color whereas 
younger specimens are decidedly reddish pink. Antennae yellowish, with the distal 
extremity black. Legs yellowish, the tarsi and the distal extremities of the tibiae 
black or brown. Labium tipped with brown. Cornicles and eyes black. 
Location: Occurring in colonies within the curled leaves of the apple. 
duration of nymphal stages 
The average length of nymphal life of the wingless spring form is 
9 to 10 days. This period is divided about equally among the four 
immature stages. Occasionally one stage will be a day or even more 
longer than the others, and such retardation of growth may occur in any 
one of the four stages. These variations are apparently due almost en¬ 
tirely to temperature conditions, although in the experiments occasional 
effects were due to poor food conditions. 
REPRODUCTION 
Reproduction commenced almost invariably about 24 hours after the 
insect had attained maturity and continued for a period of from 12 to 26 
