328 Professor EK. B. Poulton on colowr-vrelation 
| XII. | 
X. XI * Bark covered with | 
Dates in Dark purplish-brown EGE henner bright yellowish-green 
893. glossy twigs, eee powdery lichen, the colour 
probably of birch. ae of which faded and left 
the dark bark, 
= = a 
| (July 2.) 13 small | _ (July 3.) 20 larve |} 3 betwlaria, smaller | 
larvie introduced, introduced, at begin-|than in XIII and! 
a mostly in 2nd stage. | ning of second stage.| XV, introduced. 15 | 
une 27, The smallest about] bidentata, similar to | 
| .5°5 mm. long, and/those introduced in| 
none much longer. XIII. | 
e fi... Ue, dell es ees 
| | 
| Half of the larve 20counted. Afew| 3 betularia, pale, 
‘becoming purplish. becoming — reddish- | yellowish- green. 15 
July 12. _ brown. | bidentata variegated. 
| 
| 
| 
os ee | 
July 15. | Re-fed. | Re-fed. 20 counted. | Re-fed. 3 and 15 
| | counted. 
| — | 
9 on twigs, 4 on) 10 on twigs, 8 on} 2 betwlaria, mature. | 
July 18. green. green. Larve becom- | 14 bidentata, all 
ing dark  vreddish- | darkish, variegated. 
brown and variegated. | 
_— 
| | | 
| (July 24.) 12 on} 15 om twigs, 1 on| Last betularia | 
twigs, 1 on green. green, 1 on muslin. mature. 10 bidentata 
| Almost all dark. As before. ; on bark, 1 on green, 3 
| July 23. }on muslin. All varie- | 
gated brown, slightly | 
‘touched with green 
| and with white dashes 
| along Hae 
| ORR ised : 4 
| 12 on twigs, 1 on| (July 27.) 12 on| 13, all on bark (as| 
| green. 10 dark brown, | “twi igs, 4 on green, 1 | alsoon Aug. 1). About | 
| July 28. variegated ; 3 paler | on muslin, 8 changed | half darker, but all 
and less variegated. skin and of a more 
| ' uniform brown colour. 
still variegated. All 
except 2 with more | 
or less green. 
Aug. 3 
| 11 on twigs, 2 on 
12 on twigs, 
'green, 1 on muslin, 
| As before. 
14 on | 
| (July 31.) 
|green. 11 dark brown ae 1 on green. 
and more uniform | |8 yrown like the 
than before, 2 rather) twigs; 4 paler and 
paler. One or two Jess uniform ; 3 varie- 
have patches of pale gated and patched | 
green. with green. (Aug. 4.) | 
12 on bark, 1 on 
|muslin. As _ before, 
but have become 
darker. This is the 
darkest set of Experi- 
ments XII to XV. 
2 on} 
| 
| 
| 
