EXPEKIMENTS IN HYBRIDIZATION AND TEMPERATURE. 291 



ments were also made for shading appropriately portions of the 

 room. 



On Whit Monday, June 7th, 1897, the first abnormal V. urtica 

 were introduced, and so on until June 15th — in all forty-two 

 specimens, thirty-two males and ten females. 



The males were without exception very extreme forms, with 

 entirely black hind wings on the upper side ; only two females 

 belonged to this form, the remaining eight possessed blue mar- 

 ginal spots, and partly also more or less brown ground colour at 

 the anal angle of the hind wing ; certainly a very small number 

 of females, when one considers that they formed the entire 

 female aberrations from more than eight thousand pupse. 



It was interesting to note during the following weeks how 

 quickly the small creatures accustomed themselves to their 

 keeper, and lost all their fear of him, and how in certain 

 directions they exhibited intelligence and remembrance ; for 

 example, immediately on his entry into the breeding house they 

 fluttered to the ground, as they had quite apparently noted 

 that his entry was symbolical of a drink, as, to take care of 

 their thirst, I was in the habit of sprinkling the ground with 

 water. 



The 25th of June had arrived, and, in spite of the most 

 careful observation, no pairing was noted, but the room was only 

 visited between the hours of 8.30 a.m. and 7 p.m. 



All kinds of love-games were indulged in, but, as already said, 

 no real pairing. It must, however, have taken place, as, on June 

 26th, I was pleased to see a cluster of eggs on the under side of a 

 nettle-leaf, and during the following days eight females, amongst 

 them the most abnormally coloured ones, were observed laying 

 eggs. How many eggs were laid by each female on an average could 

 not be ascertained, as for many days one after another they were 

 laid on different leaves. It cannot, however, have been less than 

 two hundred, as more than two thousand larvae developed, in 

 spite of the fact that two of the ten females met an untimely end 

 through spiders. Among them, unfortunately, was the less 

 extreme of the two extreme forms. 



Probably she had laid no eggs, as the ovarium was full of 

 eggs, and she was never observed ovipositing. From July 2nd 

 the larvfe emerged, and at first were allowed to feed freely on the 

 nettle, but were later on placed in airy breeding-cases. The 

 brood of the most abnormal female was kept separate, and reared 

 from the commencement by itself. 



Unhappily, one of the many infectious diseases known under 

 the collective name of Flacherie, shortly appeared, so that of 

 all the broods only the strongest and most quickly developed 

 individuals reached the pupal stage : in all, 493 specimens. 

 These did not all produce imagines, as some were attacked by 



