3S THE ENTOMOLOGIST. 



Next, as to Goyiopteryx : G. rhamni is in the halfway con- 

 dition (column 2 on p. 9) between the species with soluble 

 yellow pigment and those with stable. And, correlated with this, 

 we have the very interesting fact that in the sister species, G. 

 cleopatra, there is already a red flush at the base of the primaries. 

 No doubt this red would at once be turned to yellow, and we may 

 fairly legitimately conclude that the total yellow would be even 

 less affected than in G. rhamni.* 



Next, in Colias,f we have converse instances: the yellow 

 is exceedingly soluble, and there are (at least so far as I am 

 aware) no red species in this genus. But — to repeat my warn- 

 ing — we must not fall into the error of applying this fallible 

 criterion too indiscriminately. Colias affords an illustration and 

 a warning: for although there may be no red species in the 

 genus, one or two extraordinary red or reddish varieties are 

 reported of C. edusa:l and a further illustration of the progress 

 which the Colias pigment is making towards red may be found 

 not only in the one or two reddish spots and borders which occur 

 on the wings, but also in the remarkable artificially-produced red 

 obtained by Mr. Edwards. 



With regard to the remaining yellow species, L. alexis calls 

 for no particular comment : and the Arctiidse have been already 

 disposed of. As to the half-dozen Geometrine species, I will 

 merely point out that whilst in none of them is the yellow 

 rapidly dissolved in the satisfactory fashion that prevails with 

 edusa, cardamines, and Delias, y-et, in not a single case is it 

 entirely obdurate : in no instance at present to hand has the 

 Geometrine yellow reached the stable stage : and correlated with 

 this we have the fact that red is almost unknown in Geometrse. I 

 am very anxious not to insist on this coincidence, or over-rate its 

 importance, since, in the present state of our knowledge, and 

 without examining a far larger number of species, it is impossible 

 to decide whether this be anything deeper than a coincidence : 

 but at least it is prima facie very significant. 



* Only since this was in type have I seen actual specimens of E. eupheno and 

 G. cleopatra : the colour which had been described to me as " red " is, I find, simply 

 deep orange, and in the former species apparently identical with the orange of 

 cardamines, with which, no doubt, it would agree in its reactions. As to cleopatra, 

 Mr. Warburg informs me that he has experimented thereon, and found the orange 

 to " disappear marvellously, the bright and intense orange being transformed to a 

 paler shade than the natural colour of the female." Nothing is said, however, as 

 to the effects on the ground yellow ; but, since Mr. Warburg has sent me specimens 

 of cleopatra, I shall be able to clear up this matter immediately. 



t In this section I had intended to redeem my promise of giving the details of 

 the experiments made in reddening the yellow of Colias. (See Entom. xxiii. 235). 

 Since my note on this subject, last July, I have continued the experiments, and 

 have obtained most unexpected and interesting results. A full account of these 

 was written out, as appendix to this subsection ; but, owing to the length to which 

 this ran, it has been found necessary to hold it over for the present. 



:|: For instance, Mr. Anderson describes a specimen displaying a " glowing rosy 

 violet "tint. Entom. xxii. p. 72. 



