12 THE entomologist's eecoed. 



I had no reason to hope for similar success, the season was already 

 late, and I should have considered myself one of the happiest of 

 naturalists if a dozen of the larvae had hybernated successfully ; 

 but even this was not to be. The dates of the four moults preceding 

 hybernation were as follows : — 1st moult, August 10th ; 2nd moult, 

 August 18th ; 3rd moult, August 26th ; 4th moult, September 10th. 

 After the 4th moult the larvte ceased to feed, although they were 

 supplied with poplar leaves. Until this time I had kept them on a 

 large branch of poplar, placed in a vase full of water and stood in a 

 breeding-cage. The larvte rested here and there on the branches, and 

 by their bluish-grey colour and flattened form assimilated perfectly 

 with the bark of the branches, and did not move the whole of the 

 winter. Knowing that heat and drought were alike injurious I placed 

 the breeding-cage in the garden, against a north w^all, taking care to 

 damp it when the weather was dry. All these precautions were in 

 vain, and in March the larvae began to fall from the branches, quite 

 dried up, and by the end of the month there were only four left. 

 Then I tried a last experiment — I planted a young poplar in my 

 garden in a position well exposed to the sun, placed on it one of the 

 remaining larvfe, covered it with muslin, and left it to fate. The 

 weather was bad, but about April 10th the sun shone on the poplar 

 a part of the day, and this appeared to waken the larva, which nibbled 

 one of the buds at the end of the branch. Seeing this I placed the 

 three other larvfe on the poplar, but it was already too late, for after 

 eating a little they died, whilst the first one continued to nibble the 

 buds, and about the middle of May, when the leaves commenced to 

 develop, the caterpillar ate much and commenced to grow, and at the 

 end of the month it moulted for the fifth and last time. This moult 

 was long and laborious ; the larva remained eight days without feed- 

 ing, then it shed its skin and in a short time became very large, and I 

 suspected it would prove to be a $ on this account. On June 20th it 

 spun its cocoon, which is soft and greyish -yellow in colour. On the 

 23rd the pupa was formed and one could see it through the cocoon, 

 and I had only to await the imago. The experiment was concluded. 

 It is necessary to keep the larvae in the sun even during the winter, 

 without this precaution they will die of hunger even by the side of the 

 leaves. On July 15th the imago emerged, a female, as I had pre- 

 dicted. The pupal state had lasted three weeks. The imago emerged 

 about 8.0 a.m., and I intended to take it into the woods in the evening, 

 in order to attract a male, but there was a heavy storm and it was 

 impossible to go out. 



As far as I am concerned there is nothing more to add. It appears 

 absolutely necessary that the larvae should pass the winter out of doors 

 on a growing poplar well exposed to the sun (a precaution necessary in 

 rearing all the Lasiocampids, each on the plant that nourishes it). It 

 is the only possible means of obtaining a successful result. I have 

 since learned that M. I'Abbe de Joannis was also unsuccessful in 

 hybernating his larvae ; he kept a part of his larvae out of doors in the 

 winter, but not in the sun. 



