NYMI'IIALIXAK: THE GENUS BRENTIIIS. 583 



and as this liistory is of" great interest, especially in comparison with 

 that of our Xew England species, we add a translation of the original 

 memoir.* ^Vt the beginning of May, 18U>, says this writer:! 



A female enphrosiue laid e^ss, Avliicli, in ten or twelve days, gave birth to little cat- 

 erpillars about tAvo millimetres long, which I fed with violet leaves. After moulting 

 three times they showed signs of uneasiness, stopped eating and hastened to attach 

 themselves here and there to the sides of the vessel containing them. At first. I 

 tliought they were preparing for a fourth moult, but I Avas soon undeceived. Their 

 body contracted, they became motionless and stiff as if dead. Yet the season Avas 

 little advanced and as they had not lacked select food, according to their taste, I did 

 not knoAv hoAv to account for this strange fact. I disturbed them Avith a feather ; 

 most of them scarcely gave a sign of life. I supplied them Avith a superabundance of 

 food, I exposed them to the sun, placed them in the open air, etc. ; five or six of them 

 clianged their position, but partook of no nourishment; they again became quiet and 

 fell once more into a lethargic state. I kept them more than a month in this condition. 

 At last, wearied Avith not seeing them resuscitate, I threAv them out of the AvindoAv, 

 blaming the fate which had thus deprived me of the opportunity of folloAving the 

 history of these caterpillars, Avliich up to this time I had cared for Avith peculiar 

 atfection. 



This unexpected result having caused me to imagine that these caterpillars Avould 

 only thrive Avell in places Avhere the maternal instinct freely deposited their germs, I 

 made no further attempt to rear them, Avhen an event inspiretl me Avith quite dirterent 

 ideas and projects. 



Three caterpillars of Arg. dia, Avhich Avere born in the early days of Septemljer 

 1825, concealed themselves under dry leaves, at the end of October, in the same Avay 

 as those of euphrosine had done. This similar habit enlightened me, made me see 

 my mistake in abandoning the latter. I then determined to raise others, resolved to 

 aAvait Avith more patience the natural destiny of my marmotic caterpillars. The mis- 

 take Avhich I made in 1819 Avas principally occasioned by considering the time at which 

 tlie torpor occurred. I did not then know any caterpillar Avhich l)ehaved in such a 

 Avay at the beginning of summer ; but Avhat rendered tlie point I mention more incon- 

 ceivable to me Avas that I kncAv very Avell that Arg. euphrosine Avas on the Aving tAvice 

 a year in our districts — first in May, afterAvards in July and August. 



HoAV, in fact, could one fully understand a lethargy ovei'takiug animals in healthy 

 condition, only half groAvn, and which moreover had flue Aveather in which to accom- 

 plish all their changes? Surely, I was not unreasonable in believing that these insects 

 could reach their full development during the Avarm Aveather. What then had so 

 deceiA'ed my hopes? Doubtless my Avards had not been carefully nursed in a natural 

 Avay ; this Avas my constantly recurring thought. 



As I'egards the caterpillars of dia, one could scarcely l)e mistaken. I readily under- 

 stood the cause of their retirement : these larvae, Avarned by the first approach of 

 cold that they could not attain the perfect state before the coming spring, were pre- 

 paring for hibernation like many other insects of very difierent species. This Avas 

 confirmed t^e f oUoAving year by the arousal and continued development of my three 

 caterpillars of dia. After noticing this I awaited with impatience the return of warm 

 weather to solve the question about Arg. euphrosine, Aviiich I had not considei-ed for 

 six years. 



* 1 had not seen the original of this memoir caterpiJIar.s from eggs (after 10-16 days) at the 



until after the publication of "The curious end of June, the middle of August and Sep- 



liistory of a butterfly-' (Amer. nat., Sept., tember. 



1872). t Vandouer, Observations sur Ja 16tbargie 



Besides the species upon which Vaudouer p(5riodique des chenilles des pnpillonseuphro- 



experiniented. B. frcija is said to winter as a sine ct dia. Mc^in. 8oc. Linn. Paris, vi : 



(■atcrpillar 20 mm. long, and B. selcne in an 37-1-378 (1827). 

 innnature condition, Scliildo having obtained 



