8 BRITISH BUTTERFLIES. 



fact, these two batches underwent their final metamorphosis together, 

 without showing any sign leading one to suspect that some were born 

 later than others. Here was a very clear and distinct account of what 

 has been long called partial double-broodedness, and which is now 

 known to occur more or less in all so-called double-brooded species in 

 north temperate climes. 



In the course of his account-, Vandouer notes the apparent slowness 

 of the feeding of the few larvae that went on to a second brood in July 

 and August, 1826 ; in fact, he evidently thought that they had a partial 

 rest in early July ; this supposition Scudder makes much of> and it is 

 . this that he really refers to in his papers as " lethargy," as apart from 

 the continued rest which he includes under the term " premature 

 hybernation." So far as our experience goes, however, the larvae, 

 forming a partial second- brood, as a rule, feed right on, e.g., Buckler 

 notes of a brood of Brenthis selene, that the larvae hatched June 22nd, 

 1870, that, for a time, all fed level; then he divided them, putting one 

 part into a hothouse, and leaving the other part outside ; one of the 

 outside lot was noted on July 18th still feeding, and, by the 30th, was 

 f ullfed, all the others (both inside the hothouse and outside) remaining 

 quite dormant, being about -375in. in length when they commenced to 

 hybernate. This remarkable phenomenon is much more common in 

 B. selene, etc., in the neighbourhood of Torre Pellice, in Piedmont, 

 where a large second-brood occurs in early August. But the 

 peculiarities observed occur also in almost all our British species that 

 are partially double- or triple- brooded, e.g., Rumicia phlaeas, Cupido 

 minima, Aricia astrarche, Agriades bellargus, Polyommatus icarus, 

 Pararge megaera, Coenonympha pamphilus, etc., and it was also recorded 

 in the hot summer of 1893, in Dry as paphia. In these species, the 

 eggs laid in May or June by the $ s of the first brood of the first series all 

 hatch in due course, e.g., in June or July, the larvae, kept under identical 

 conditions of temperature, moisture, food, etc., from the very first feed 

 at different rates, and, whilst a " forward " lot go ahead, pupate, and 

 produce imagines in August, a " laggard " lot reach a certain point, 

 the natural hybernating instar, and there remain throughout the rest 

 of the summer, autumn, and winter, until the spring, before arousing 

 themselves from the lethargy into which they have fallen. Scudder's 

 attempt to distinguish between those larvae that commence early to 

 aestivate, and continue without break their aestivation into hybernation, 

 calling the summer resting " lethargy," is, therefore, purely artificial, 

 although, occasionally, individuals of the second and third broods do 

 commence a formal hybernation in the summer, and then yield and go on. 

 He says : " This same feature (lethargy) occurs in some of our North 

 American species of Brenthis, as I have several times observed. It is also 

 found in some of the Alelitaeini, and, I suspect, also in the genus Argynnis." 

 As we have already said, there are many well-known illustrations of larvae 

 presenting this phenomenon in Europe, especially in southern Europe; 

 e.g., Brenthis selene, Melitaea cinxia, M. didyma, etc., in which the larvae 

 from eggs laid in May develop unequally, some of the larvae not resting at 

 all, but which, feeding up rapidly, produce pupae and imagines in August, 

 whilst their brothers and sisters, having reached the normal hyberna- 

 ting stage, commence their resting in July or August ; and the August 

 imagines, laying eggs in due course, produce larvae that go on to the 

 same resting-period, and then hybernate with their uncles and aunts, 



