SEASONAL DIMORPHISIM OF LEPIDOPTERA. 33 



than the German phtoeas, and even than Sardinian phlocas of the 

 spring brood. 



Lot B. — These larvae were at the commencement of their 

 pupation placed in the cellar or the refrigerator. As pupation 

 at the temperature of the latter, 6-10° C, did not generally take 

 place, they had to be taken out again, and were brought into the 

 temperature of the cellar, at little over 10° C. Under these 

 circumstances pupation was delayed for a very long time, and 

 lasted over a month (from June 22nd to July 25th). The pupae 

 then remained in the refrigerator at from 7-10° C, where 

 several butterflies emerged between Aug. 27th and Sept. 16th. 

 It was evident, however, that the dampness of the refrigerator 

 not infrequently rendered the red quite pale yellow, so some of 

 the pupae still remaining were brought into a room, where 18 

 more butterflies emerged between Sept. 17th and Oct. 18th. 

 The rest remained in the refrigerator, and by-and-by emerged 

 at 10-11° C, most of them crippled, although very few to such 

 an extent, that the colour could not have been recognized. In 

 reference to brilliancy of colour, it was all one, whether the pupae 

 emerged in the refrigerator or in the room. 



Of the 51 butterflies that emerged, only two are somewhat 

 powdered with black, one of which emerged on Aug. 27th, and 

 the other on Sept. 15th. All the others are bright red-gold, and 

 have very small black spots ; but the majority have a broad and 

 deep black margin, and especially the black of the apex of the 

 wing often spreads to the uppermost spot of the band of spots, 

 while at the same time it extends as a broader stripe along the 

 costa to the base of the wing. These are characters, which are not 

 present in German specimens ; it is such a mixture of characters 

 of the southern and northern forms as is unknown to me in 

 specimens captured at large. 



The duration of a lower temperature for a very long time does 

 not produce any increase of the effect, that can be recognized. 

 To be sure the two darkest specimens emerged tolerably early, 

 viz. on Aug. 27th and Sept. 15th, but perfectly bright specimens 

 emerged on Aug. 31st, Sept. 5th, 6th, 7th, and 10th, and then 

 again some rather darker specimens on Sept. 20th. 



B. Experiments with a Brood from German Parents, 



(3) Eggs reared at an increased Temperature. — A female cap- 

 tured at Leipzig in the middle of August, 1889, laid eggs, which 

 were forwarded to me at Lindau, on the Lake of Constance, 

 where I received them on Aug. 20th. As I.did not know, whether 

 the eggs of phloeas hybernated or not, I placed them at first in 

 an unheated room having at that time a temperature of no more 

 than 10° C. However, the first larva hatched on Aug. 27th. 

 Thereupon I placed all the eggs in a hothouse, in which the 



