56 THE ENTokotiOGlst. 



of other reds. Its red dissolved in the acids (except apparently 

 in H2SiF6) just as, e.g., urticce chestnut does; and in conse- 

 quence of this it was, of course, entirely imjjossible to restore the 

 red by washing and neutralising. The further consideration of 

 this exceptional and interesting species I am purposely deferring 

 until after we have considered the nature of the chestnut pig- 

 ment, from which, and not from yelloiv, the atalanta red is, I 

 think, certainly derived. 



We will now return to the B. batch. These (the duplicates 

 of A.) were started on June 1st. (except the Deiopeia wings, 

 which were started a week later). After one hour's exposure, 

 the acid was simply poured off, as completely as possible, — the 

 wings not being ivashed or neutralised at all, — and the watch- 

 glasses (to which the wings were gummed) were then inverted 

 and left standing on gauze-covered box-lids; the object of this 

 treatment was to ensure that, in the first place, the residual acid 

 (which of course cannot be poured ofl) should have an oppor- 

 tunity of running off the wing instead of accumulating on it, as 

 would be the case if the wing were left in the lowest position 

 {i.e., in the centre of a concave watch-glass) ; and, in the second 

 place, to ensure the access of plenty of air, and, in fact, secure 

 ventilation ; for it appeared to be possible that air might slowly 

 produce the same effect as washing does quickly.* 



These wings were left alone for many weeks, or in some 

 cases months, and the following are the entries made at intervals 

 in my note-book, as to the progress of the experiments : — 



June 8th (one week). None of these wings show the least 

 reversion to red as yet. 



June 22nd (3 weeks, except for D. bella, 3 weeks). The 

 following show no signs of reversion to red : — 



V. atalanta. HCl, HNO3, H2SO4, HaSiFe (= all). 



C. hera. HCl, HNO3, H2SO4, HgSiFe, C2H2O4 {= all). 



C. nupta. HCl, HNO3, H2SO4, C2H2O4 (= all). 



Also E. jacobcece. HNO3. 



Z.filipendulcs. H2SO4. 



The following have somewhat reverted to red : — 



Deiopeia bella HCl (after 2 weeks, that is). 



E. jacobcece. HCl (and H2SiF6 : this had been originally the 

 least completely yellowed). 



The following have entirely reverted to red : — 



Z.filipendulce. HCl,f H2SiF6 (emphatically so). 



August 3rd (9 weeks). The above-noted reversions are per- 

 manent {viz. Jilipendulcs, HClf and H2SiF6). 



* This is what I mean by the " time effect,"— not the most happily chosen 

 term, I admit. 



t This is the entry in my note^book : but it must be a lapsus pennce intended 

 almost certainly for H2SO4. 



