72 THE ENTOMOLOGIST S RECORD. 



did succeed in emerging when exposed artificially to a much higher 

 temperature than that to which it is probable even the summer brood 

 is exposed in a state of nature in this country, and, perhaps, if 

 heat had been applied to the pupae earlier, the whole brood would 

 have emerged successfully. 



But the numerous experiments which have been condvicted with 

 the present species, show conclusively that it is able to withstand a 

 much greater amount of cold than this particular brood was subjected 

 to at any time. To quote only one or two, Weismann*''' records that 

 a number of eggs and small larvae were found on July 6th ; a portion 

 of these were reared throughout in a cellar at a temperature of 15°C. 

 (59'^ Fah.). Pupation began on August 7th, and the butterflies 

 emerged on August 27th and 29th. It is not recorded that any of 

 the imagines failed to emerge, or were otherwise injured by the low 

 temperature. Standfussf says that pupiie kept in a refrigerator for 

 32 days, produced imagines after being 9-10 days in a room 

 at normal temperature. Further, that pupae were kept upon ice for no 

 less than 42 days, and these produced imagines after 13-14 days in 

 the room. 



These experiments show that the species is able to withstand a 

 very considerable amount of cold without fatal result, and suggest 

 that the direct action of cold could not have been the cause of failure 

 in the present case. It is not improbable that there may be patho- 

 logical influences of which little or nothing is at present known, and 

 that very late — or otherwise abnormal — broods are more open to such 

 than those which occur at the usual time, and under normal conditions. 



It is remarkable that so little has been hitherto recorded of the 

 third brood. Mr. Wolfe records the finding of larvae in September at 

 Skibbereen {Ent. Rec, iv., 270), and Mr. Tutt received full-fed larvae 

 from Cambridge ; these pupated at once, the imagines emerging during 

 the second week in October. Another batch from Darlington were 

 small, and did not produce imagines until October 20th-22nd (Ihid, 

 p. 291). 



Although these late broods are rarely observed in this country, they 

 must be much more frequent — if not the rule — in the southern area of 

 its distribution. A note by Mr. Tutt {Ent. Bee, ix., p. 225) is very 

 suggestive. He found larvae abundantly at Digne in April. The 

 earliest of these produced imagines on May 5th at Brighton, that is 

 to say nearly five weeks earlier than the normal time of emergence in 

 England. 



Cannot entomologists who reside in the south of Europe — and are 

 thus able to observe the species throughout the year — give us a little 

 information ? It is curious that nearly all authors (with the excep- 

 tion of Tutt, Brit. Butts., p. 339) ignore the existence of a third 

 brood altogether, and are by no means agreed in respect to the other 

 two. A few notes may be instructive. Newman was aware that the 

 species sometimes occurred very late, for after quoting a note by 

 Mr. Doubleday, he says, " Thus there are evidently two broods in the 

 year, and June and September may be given as the dates for their 

 appearance. Some of the second brood remain until October in the 

 chrysalid state, and Mr. Clogg has observed the emergence of speci- 

 mens on the 22nd and 25th of December " {Brit. Butts., p. 54). It is 

 * Entomologist, xxix., pp. 174-175, t I^i^i xxviii., p. IO7. 



