254 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
averaged the antennae of migrants of the two hosts separately and col¬ 
lectively in Table VIII. The wide range of variation in the antennae 
of Eriosoma lanigera is well shown in the range for the 29 antennae 
measured. It is such that it might well embrace the measurements 
given for Eriosoma cratcegi by Davis in Volume 3, No. 5 of this 
Journal. 
Table VIII 
I 
II 
III 
IV 
V 
VI 
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. 
Thirteen Antennas from Apple Migrants 
Average. 
.059 
.062 
.369 
20 
.111 
4 
.119 
6 
.087 
1 
Minimum. 
.051 
.051 
.320 
16 
.088* 
3 
100 
5 
.072 
0 
Maximum. .. . 
.068 
.073 
.416 
22 
.131 
7 
.128 
7 
.096 
2 
Sixteen Antennae from Crataegus Migrants 
Average. 
.060 
.060 
.423 
27 
.122 
6 
.147 
8 
.109 
3 
Minimum. . .. 
.051 
.051 
.368 
24 
.112 
5 
.120 
6 
.085 
0 
Maximum. .. . 
.064 
.064 
.462 
29 
.135 
7 
.160 
10 
.118 
5 
Thirteen Antennae from Apple and Sixteen Antennae from Crataegus Migrants 
Average. 
.060 
.061 
.389 
23 
.117 
5 
.134 
7 
.099 
2 
Minimum. 
.051 
.051 
.320 
16 
.088* 
3 
.100 
5 
.072 
0 
Maximum. . . . 
.068 
.073 
.462 
29 
.135 
7 
.160 
10 
.118 
5 
*The smallest segment IV was on slide 3. It measured .072 but appeared somewhat abnormal. 
Explanation op Plate 6 
1 and 2. Antennae from migrants out of control colony on apple established from, 
the offspring of a spring migrant. 
3. Antenna from fall migrant taken from colony on potted apple tree. 
4. Antenna from fall migrant out of colony established on apple with apterous 
vivipariae from Crataegus. (Colony Ca-A5 of Table V.) 
5. Antenna from fall migrant out of control colony established on Crataegus from 
spring migrant. 
6-8 inclusive. Antennae from fall migrants out of colonies established on Crataegus 
with apterous vivipariae from apple. (Colonies Aa-C18 and Aa-C20 of Table VI.) 
9. Antenna of fall migrant of Eriosoma cratcegi taken from mount loaned me by 
A. C. Baker. 
The two lower pictures represent normal and infested elm buds collected at the 
same time, April 6,1917 and from the same tree. 
