April, '18] 
BECKER: WOOLLY APHIS 
253 
Eriosoma cratcegi Oestlund 
Mounts were made of the fall migrants of Eriosoma lanigera se¬ 
cured from different sources (apple and Crataegus), with a view of 
determining the effect of the host on the antennae of the aphids. The 
results are tabulated in Table VII. The table gives the measurements 
of the segments in mm. The number of annulations of the segments 
is also given. 
The following explanation is given for the slide numbers. 
Slide 1 .—From control colony on apple reared from a spring migrant in 1917. 
Slide 2 .—From a control colony on Crataegus reared from a spring migrant in 1915. 
Slides 3 and 4 -—From colonies on potted apple trees which were presumably started 
by spring migrants in 1917. 
Slide 5 .—From the same source as Slide 2. 
Slide 6 .—From apple colony established by transferring apterous vivipariae from 
Crataegus in 1917. (Colony Ca-A5 of Table V.) 
Slides 7 to 11 inclusive .—From Crataegus colonies established by transferring ap¬ 
terous vivipariae from apple in 191^. (Colonies Aa-C18 and Aa-C20 of Table IV.) 
Table VII 
I 
II 
III 
IV 
V 
VI 
Slide 
No. 
Meas. 
Meas. 
Meas. 
An. 
Meas. 
An. 
Meas. 
An. 
Meas. 
An. 
in mm. 
in mm. 
in mm. 
No. 
in mm. 
No. 
in mm. 
No. 
in mm. 
No. 
1 
.068 
.073 
.416 
22 
.124 
5 
.124 
7 
.088 
0 
1 
.061 
.065 
.415 
26 
.112 
6 
.112 
6 
.084 
0 
2 
.061 
.064 
.432 
27 
.124 
5 
.146 
8 
.085 
1 
3 
.059 
.056 
.320 
16 
.108 
4 
.112 
5 
.085 
2 
3 
.064 
.335 
18 
.072 
3 
.120 
5 
.092 
1 
3 
.064 
.064 
.382 
20 
.130 
7 
.126 
6 
.096 
2 
3 
.365 
20 
.131 
6 
.128 
5 
.092 
0 
4 
.056 
.064 
.400 
21 
.112 
4 
.128 
7 
.088 
0 
4 
.064 
.400 
20 
.128 
5 
.120 
5 
.096 
1 
4 
.058 
.066 
.365 
18 
.112 
5 
.115 
5 
.086 
0 
5 
.059 
.060 
.455 
28 
.120 
6 
.141 
7 
.096 
2 
5 
.064 
.064 
.440 
27 
.112 
6 
.120 
7 
.104 
2 
5 
.056 
.462 
29 
.120 
6 
.144 
8 
.112 
2 
6 
.051 
.342 
20 
.096 
3 
.110 
5 
.090 
1 
6 
.056 
.053 
.343 
20 
.120 
4 
.123 
6 
.072 
1 
6 
.051 
.061 
.343 
18 
.110 
3 
.123 
6 
.083 
1 
6 
.088 
3 
.100 
5 
.075 
2 
7 
.056 
.375 
24 
.120 
5 
.128 
6 
.112 
3 
8 
,05i 
.051 
.400 
24 
.120 
7 
.131 
7 
.112 
4 
8 
.... 
.420 
25 
.131 
6 
.152 
10 
.115 
3 
8 
.... 
.112 
5 
.152 
8 
.115 
5 
9 
.064 
.368 
.112 
7 
.148 
8 
.112 
3 
9 
.064 
.064 
.405 
27 
.112 
7 
.156 
8 
.112 
3 
9 
.064 
.061 
.420 
27 
.135 
7 
.152 
8 
.112 
4 
9 
.064 
.061 
.430 
28 
.128 
7 
.152 
10 
.112 
3 
10 
.061 
.431 
27 
.128 
6 
.160 
7 
.115 
3 
10 
.064 
.430 
25 
.135 
7 
.160 
8 
.118 
3 
11 
.056 
.056 
.430 
25 
.120 
6 
.155 
8 
.096 
2 
11 
.056 
.440 
28 
.128 
6 
.148 
9 
.112 
2 
It appears from a study of the 13 antennae of apple migrants and the 
16 antennae of Crataegus migrants that the antennae of the latter are 
usually longer than those of the apple migrants. Especially is this the 
case in segments III, V and VI. For convenience the writer has 
7 
