VARIATION AND ABERRATION IN BUTTERFLIES. 107 



The blue spots on the outer margin, especially of the fore 

 wing, disappear, as also do more or less the pair of spots in the 

 middle of the fore wing. 



The black spot on the dorsal margin becomes at least much 

 smaller ; in one specimen it has all but gone. Moreover, the 

 black basal patch on the hind wing is substantially lessened in 

 extent. The under side of both wings is conspicuously darker. 



To speak briefly, these points indicate an approach to var. 

 icJinusa, Bon., which form indeed would be produced in its 

 typical aspect if all the characteristics mentioned were united in 

 one individual. Amongst the material so far before me, how- 

 ever, there is no such individual to be found. But all these 

 characteristics indicate a certain approach of the ordinary type 

 of r. iirticce, L., to V. io, L. 



b. Cold. 



Pupre kept 32 days in the refrigerator gave the perfect insect 

 after 9 — 10 more days in the room. 



The blue on the outer border is much increased ; the black 

 spots on the costal margin and in the middle of the wing, aud 

 more particularly the spot on the dorsal margin, show an in- 

 crease in size and depth of colouring. In one-fourth of the 

 specimens obtained there appeared a black transverse shade 

 between the largest costal spot and the spot on the dorsal margin, 

 so that a third, and in many individuals almost one-half, of the 

 fore wing seemed blackened from the base outwards. 



These specimens, by the above-mentioned characters, strongly 

 recall the North American V. milherti, Godt. ; they are, however, 

 readily distinguished by one handsome feature not possessed by 

 T". inilberti, viz., the specially strong development of the blue of 

 the outer border, and the presence of blue streaks extending from 

 the white costal spot to the apex of the fore wing. The under 

 side of the hind wing is darker than in normal specimens, as are 

 also the tip and basal portion of the fore wing. 



Pupffi of T'. urticiB kept upon ice for 42 days, and emerging in 

 the room 13 — 14 days afterwards, lost all but a small relic of the 

 beautiful blue spots on the outer border, and, so far as the black 

 markings are concerned, show on the whole less deviation from 

 the normal form than the specimens just described, which re- 

 mained in the refrigerator as pupre for 32 days. Many of these 

 specimens are indistinguishable from the northern var. polaris. 



5. Vanessa io, L. 

 a. Warmth. 

 Pupffi kept 72 hours at 37' C. (98°— 99° F.) produced the 

 perfect insects in 4 or 5 days afterwards. These were of the 

 ordinary form with but slight modification. 



The ground colour of the fore wings becomes of a darker 



