328 



Professor E. B. Puulton on colour -relation 



Dates in 

 1893. 



June 27. 



X. 



Dark pui-i)lisli-brown 



glossy twigs, 



probalily nf Ijii'ch. 



(July 2.) 13 small 

 larvre introduced, 

 mostly ill 2nd stage. 



XI. 



llc'ddisli-ljiowii 

 twigs. 



(Julys.) 20 larvs 

 introduced, at begin- 

 ning of second stage. 

 The smallest about 

 5*5 mm. long, and 

 none much longer. 



XII. 



Bark covered with 



bright yello-wishgrecu 



powdery lichen, the colour 



of which faded and left 



the dark bark. 



Half of the larvoe 20 counted, A few- 

 becoming purplisli. : becoming reddish- 

 July 12. I 1 brown. 



Re-fed. 



Re-fed. 20 counted. 



9 on twigs, 4 

 July 18. green. 



10 on twigs, 8 on 

 green. Larv;e becom- 

 ing dark reddish- 

 brown and variegated. 



July 23. 



(July 24.) 12 on j 15 on twigs, 1 on 

 twigs, 1 on green, i green, 1 on muslin. 

 Almost all dark. I As before. 



July 28. 



3 hctularia, smaller 

 than in XIII and 

 XV, introduced. 15 

 hidentata, .similar to 

 those introduced in 

 XIII. 



3 helularia, pale 

 yellowish - green. 15 

 hidentata variegated. 



Re-fed. 

 counted. 



3 and 15 



2 helularia, mature. 

 14 hidentata, all 

 darkish, variegated. 



Last hctularia 



mature. 10 hidentata 

 on bark, 1 on green, 3 

 on muslin. All varie- 

 gated brown, slightly 

 touched witli green 

 and with white dashes ' 

 along sides. 



12 on twigs, 1 on (July 27.) 12 on ' 13, all on bark (as 

 green. 10 dark brown, twigs, 4 on green, 1 also on Aug. 1). About 



variegated; 3 paler on muslin. 8 changed 



and less variegated. skin and of a more 



uniform brown colour. 



half darker, but all ' 

 still variegated. All ' 

 except 2 with more ! 

 or less green. ' 



Aug. 3. 



11 on twigs, 2 on 

 green. 11 dark brown 

 and more uniform 

 than before, 2 rather 

 paler. One or two 

 have patches of pale 



(July 31.) 14 on 

 twigs, 1 on gi'een. 

 8 brown like the 

 twigs ; 4 paler and 

 less uniform ; 3 varie- 

 gated and patched [ nients XII to XV. 

 with green. (Aug. 4.) 

 12 on twigs, 2 on 

 gi'een, 1 on muslin. 

 A.S before. 



12 on bark, 1 on 

 muslin. As before, 

 but have become 

 darker. This is the 

 darkest set of E.vperi- 



