3 2 4 
Journal of Agricultural Research 
Vol. VTI, No. 7 
Table II .—Relative proportions of antennce and number of sensoria of winged forms of 
Aphis sorbi and A. malifoliae 
Aphis sorbi. 
Aphis malifoliae. 
Segment 
in. 
Segment 
IV. 
Segment 
V. 
Segment 
VI. 
Segment 
III. 
Segment 
. IV. 
Segment 
V. 
Segment 
VI. 
i 
d 
i 
4 
i 
f 
i 
i 
4 
1 
3 
bo 
1 
4 
1 
i 
5 
i 
s 
*4 
1 
I 
1 
£ 
tt 
§ 
S 
a 
1 
s 
a 
i 
S 
4 
1 
Bast 
& 
34 
61 
23 
23 
19 
15 
IO 
28 
36 
60 
23 
29 
15 
7 
6 
3 ° 
34 
60 
24 
25 
20 
10 
IO 
27 
38 
53 
24 
27 
16 
6 
6 
32 
34 
53 
2 3 
24 
20 
13 
10 
29 
37 
55 
24 
27 
17 
10 
7 
35 
34 
67 
24 
24 
21 
11 
9 
27 
37 
63 
21 
22 
15 
7 
6 
35 
35 
57 
22 
24 
l8 
9 
9 
26 
36 
53 
24 
27 
17 
5 
7 
35 
35 
64 
24 
24 
20 
11 
10 
27 
35 
54 
22 
23 
14 
4 
6 
3 i 
Aphis kochii Schouteden, 1903 (PI. 20, B).—This name was given 
by Schouteden (6, p. 185) to the species described as A. pyri by Koch, 
since Boyer's species already was called by that name. It was found 
by Koch curling the leaves of Pyrus pyraster . The description given 
by Koch does not agree with our apple insect, but it does agree with 
another species occurring on apple in Germany, of which the writers 
have specimens. Two species were collected from the apple in Ger¬ 
many at the same time, one which seems undoubtedly to be A . malifoliae 
and another which is very similar to it but having short cornicles. 
In describing his A . pyri Koch says (3, p. 60): “ Honigrohrchen sehr 
kurz, etwas walzenformig.” His figures also show short cornicles which 
are very unlike those of the rosy aphis, but very much like those of the 
other species. The writers believe, therefore, that A . kochii is quite a 
distinct species from A . malifoliae} 
Myzus plantaginis Passerini? (PI. 24, A ).—A species of Myzus occur¬ 
ring commonly on the broad-leaved plantain in this country must be 
distinguished from the rosy apple aphis occurring on plants of the same 
genus. This is a very simple process where winged forms of the species 
are present. These have the wing veins bordered with dusky, giving 
the venation a much heavier appearance than it has in the rosy aphis. 
The third segment, moreover, of the antennae has one simple row of 
sensoria, whereas the same segment of the rosy aphis is crowded with 
sensoria. When, however, only wingless forms are present, the two 
species look remarkably alike and there would seem to be almost as 
much reason for calling the one a species of Myzus as the other. The 
measurements, too, are very similar, but Segment V of M. plantaginis 
nearly always averages a little longer than Segment IV, whereas in the 
1 Since the account just given was written, Theobald (io. p. 202-210) places A. malifoliae Fitch, 1856, as • 
a synonym of A. kochii Schouteden, 1903. As shown herein, the two are distinct, but A. pyri Boyer of 
Koch is A. malifoliae Fitch. 
