VARIATION AND ABERRATION IN RUTTERFLIES. 105 



specimens almost entirely so. The thorax also is rendered much 

 lighter in colour by an increase in the number of yellow scales. 



Under side. In correspondence with the modification of the 

 upper side, much of the black marking is obliterated by yellow 

 scales. In two specimens, for example, the black marginal line 

 has completely disappeared, with the exception of a few black 

 scales constituting a scarcely perce[)tible relic. 



Some of these specimens, as already remarked, bear a perfect 

 resemblance to those that fly in August in the neighbourhood of 

 Antioch and Jerusalem. 



b. Cold. 



One portion of the pupae, consisting of 24 specimens, which 

 were kept for 28 days in the refrigerator, yielded only two 

 specimens. These resemble the Swiss and German form of 

 P. macliaon, L., from hybernated pupae. 



With regard to AjxUura iris, h., A. ilia, Schiff, and Limenitis 

 Camilla, Schiff, the material subjected to experiment was not 

 sufficient to give any certain conclusion. 



2. Vanessa c-album. 



a. Warmth. 

 This species also, like P. machaon, L., whether at a raised or 

 a lowered temperature, gave rise only to forms such as those 

 occurring on the earth at the present time. Pupae kept at 37° C. 

 (98° — 99° F.) gave origin, after 6—8 days, to the light-coloured, 

 yellowish-brown form of the butterfly, especially pale on the 

 under surface, with less sharply defined markings and less deeply 

 indented margins to the wings. 



h. Cold. 



Pupae kept on the ice for 28 days produced, after 7 — 10 days 

 more, the form with much more sharply defined markings, a 

 considerably darker under side, in many cases mingled with moss- 

 green tints, and a more deei)ly indented margin to the wings. 



An exact comparison of the measurement of the wings makes 

 it extremely probable that the modified shape of the wings in the 

 "warmed" form of P. macJuion, h., arises from the fact that 

 certain of the nervures are much elongated as compared with the 

 "cooled" form; whereas the more deeply indented margin of 

 the " cooled" form of V. c-albiun is due to arrested development 

 of certain parts of the wing, especially the intercostal portions. 



3. V. ijolychloros, L. 



a. Warmth. 



Five days at 37° C. (98°-99° F.), then at 25° C. up to the 



emergence of the butterflies on the 9th — 12th day. The result 



was a reduction of the blue marginal spots of the hind wing and 



of the dark outer border of the fore wing. There was also a 



