Nov. 13, 1916 
Rosy Apple Aphis 
33i 
winged they would have been unable to exist upon apple, but must have 
flown to plantain. Any young which they might possibly have deposited 
upon apple would have died soon after birth. 
The two intermediates in question continued feeding upon apple after 
becoming adult, produced their young normally, and these, in turn, 
produced spring migrants, which left the apple. In other words, the two 
intermediates not only evince a change of form from winged toward 
wingless, but also a like change in habit. 
In discussing the intermediates of Aphis pomi the writers (9) have 
advanced the suggestion that the winged form and bisexual reproduc¬ 
tion represent the more primitive condition among aphids and that 
these insects are at present in an active state of variation toward a 
wingless form and parthenogenetic reproduction. If this supposition is 
correct, the present examples would indicate that the alternation of 
hosts is a more primitive condition, even possibly that the aphids were 
originally general feeders and that some of them are varying toward 
forms which will feed only upon one host. 
DESCRIPTION 
Morphological characters: Antennae of about equal proportions in both specimens. 
Segment III, 0.576 mm.; IV, 0.352 mm.; V, 0.288 mm.; VI, baseo.112 mm.; unguis, 
0.576 mm. One specimen has 6 sensoria near the distal extremity of III, 15 on IV, 
and 3 on V. The other specimen has both antennae with the following sensoria; 
32 and 38 on Segment III, 17 and 21 on IV, 3 and 4 on V. Cornicles in one specimen 
0.4 mm. long and in the other 0.448 mm. Winged fhoracic characters absent. Wings 
represented by small padlike structures 0.32 mm. long in one specimen and 0.16 mm. 
long in the other. 
Color characters: General appearance and color resembling those of the wingless 
form. 
SPRING MIGRANT 
DESCRIPTION 
Since the forms of the first three instars show little difference between 
those which become wingless and those which become winged no descrip¬ 
tion is here given of the first three instars of the spring migrant. 
Fourth instar (pupa). —Morphological characters. Antennae with the following 
measurements: Segment III, 0.384 to 0.432 mm., average 0.414 mm.; IV, 0.24 to 
0.32 mm., average 0.28 mm.; V, 0.176 to 0.216 mm., average 0.2 mm.; VI, (0.08 
plus 0.4 mm.) to (0.112 plus 0.512 mm.), average (0.96 plus 0.433 mm.). Cornicles 
0.256 to 0.32 mm., average 0.272 mm. 
Color characters: Thorax and wing pads pink, shaded with dusky at the tips of the 
pads. Top of head and first two antennal segments bluish dusky; Segments III and 
IV of antennae whitish, distal segments black. Abdomen slaty blue, the embryos show¬ 
ing through as yellowish white patches. The covering of mealy wax gives a grayish cast 
to the abdomen. Between the cornicles and caudad of them a dull rusty area, not a 
bright rusty area as in the wingless individuals. Lateral and caudal tubercles 
showing as minute dark brown spots. Cornicles brownish black. Legs whitish 
with the exception of the tarsi and the distal tips of the tibiae. Labium tipped with 
black or dark brown. Byes dark brown. 
