322 



Pi-ofessor E. B. Poulton on colour-relation 



Dates in 1893. 



May 22. 

 (E. 13. P.) 



June 11. 

 (E. B. P.) 



June 19. 

 (E. B. P.) 



June 25. 

 (E. B. P.) 



July 1. 

 (E. B. P.) 



July 6. 



Careful com- 

 parison on 



white paper. 

 (E. B. P.) 



Black twigs of 

 Turkish oak. 



II. 



Deep blue paper 



spills. 



Ifi Young larvae 

 introduced. 



(June 9.) Re-fed. 



III. 

 Dark purplish-brown 

 glossy twigs probably 

 1 of bu-ch. 



IV. 



White-spotted 



purplish-brown twigs 



of birch. 



(May 23.) 15 15 larva in- 16 young larvae 

 young larvae in- troduced (just i introduced, 

 troduced. ' hatched). 



121arva3 counted; 

 becoming very 

 dark. 



(June 17.) All All 

 15 very black like , dark, 

 the twigs. 



12 very 



(June 16). All 

 15 dark like the 

 twigs, but not 

 markedly purplish. 



All 15 on twigs, 

 very dark and 

 purplish. 



15 counted. 



(June 22.) As 

 before. All at rest 

 on twigs. 



As before, 

 on spills. 



All 



As before 

 on twigs. 



all 



2 at rest on 

 green, 13 on twigs. 



AH very black. 



July 10. 2 at rest on 



(W. Holland. ) \ green, 13 on twigs. 

 All verv black. 



July 12. 

 (W. Holland.) 



15 on twigs. 



9 on spills, 1 on 

 green, 2 not noted. 

 All 12 of a uniform 

 dark purplish- 

 black. 



12 larva} on 

 twigs, 4 on green. 

 All dark, but 

 greyer than those 

 in III, and not so 

 dark as latter. 



(June 27.) All 

 15 dark brown. 



(June 27.) Re-fed. 



8 on spills, 4 on 

 green. All very 

 dark. 



9 on spills, 3 on 

 green. 



All 15 on twigs. 

 All very dark. 



13 on twigs, 3 

 on green. Dark, 

 but much lighter 

 and less constant 

 than III. 



14 on twigs, 1 ! 15 on twigs, 1 



on green. All dark on green. The 



purplish-brown. larvae remain 



: lighter in tint 



than III. 



13 on twigs, 2 

 on green. 



13 on twigs, 3 

 on leaves. 



