280 



THE ENTOMOLOGIST. 



spot was covered by a piece of the ground colour. I found, 

 however, that the colour- effect of ichnusa did not appear till I 

 had, with the help of a light orange-yellow specimen of urtitue, 

 also patched out the light yellow costal spots with the darker 

 colour and filled in the basal wiug part as in ichnusa. The 

 hind wing was also made to look like fig. Irt, and then it was 

 interesting to see how different in colour the two wing pairs, of 

 which the left one had remained untouched urtiae, appeared 

 to have become. The ground colour in the right wiug pair was 

 the same as in the left, yet it looked more fiery, more brilliant. 

 Still, the shape of the wings, the less dentate outer margin, 

 more " pointed" apical projection, and the peculiar arrangement 

 of the blue spots disturbed the effect slightly ; but the resem- 

 blance to ichnusa was sufficiently striking, and the alterations 

 necessary to obtain this resemblance were great enough to show 

 how hopelessly far from ichnusa were the aberrations of urticce, 

 which merely exhibited a reduction of the black and yellow 

 markings. Not yet, as far as I could learn, have the black 

 markings of urticce aberrations appeared in the relative position 

 they occupy in ichnusa. I will here note, however, that when 

 in V. io the black inner marginal spot appears, as it occasionally 

 does, then it occupies the same relative position in the wing as 

 in ichnusa. I possess a few specimens of aberrative V. urticce, 

 which show this spot much as in ichnusa, but the puncta do not 

 follow suit, nor does any other part of the facies, except the 

 basal suffusion, do so. The corresponding parts of the under 

 side in urticce are generally nearer ichnusa than the upper side ; 

 this can be easily seen by holding the specimens against the 

 light, when very often the inner marginal spot will be found to 

 jut out far beyond the correlated black under side markings. 

 The basal portions of the fore wings in urticce cloud up occasion- 

 ally under the influence of retarded pupal development (pupal 

 aberration), or of retarded larval development, also if caused 

 by insufficient food (larval aberration), exactly as in ichnusa. 

 I have examples of both categories with the base like icJinusa 

 (ab. basi-ichnusa — not to be mistaken for a dark form in 

 which the wing base is much suffused with black and dark 

 brown-red scales mostly extending to the median wing-area, as 

 in V. milherti — ab. hasi-milherti*) , but they are otherwise little 

 different from normal urticce. 



In different aberrations of V. urticce I also found most of the 

 other ichnusa-ioim. details, but I have not yet seen them all 

 together in one specimen, and the important displacement of the 



■•' An extreme form of this fine aberration emerged last year, on the 

 25th of July, in my cases together with some transitional forms, from pupae 

 oione brood of wild Herts larvce, which developed under normal conditions 

 in the mean temperature of the season. I had expected to rear only normal 

 specimens, which I wanted for purposes of comparison. 



