XLirr 



the Bio/ogisc/ics Centra /b/a/t of Aug. 20"" 191 3 and in Nature Nov. 21" of the 

 same year. As early as 1 896 in part XXXIX of the Nedcrlandsche Tijdschrift 

 voor Entomologie Dr. Oudemans asserted that he had observed the same thing 

 in the chrysaHs of Acherontia Atropos L. I have bred the very common 

 AcHERONTiA Lachesis Y. of Java in great numbers there, without however, ever 

 hearing any sound. It certainly did draw my attention, that on the pupae of 

 this species of Fleterocera there were shragreened stripes of the same sort as 

 belong to the stridulation organs of other insects. Similarly some insects are 

 seen to go through rubbing movements, just the same as those which in other 

 kinds produce a sound, but without any sound being heard. This is probably 

 due to the limitations of human hearing, which is unable to perceive the sound 

 produced by some insects. Is it possible that the stripes on the pupae of 

 Acherontia Lachesis F. present a similar case? The rubbing together of 

 the secondaries by some Lycaenidae referred to on p. vi may point to the same 

 thing, although no organs can be discerned which give any ground for this 

 supposition. What I certainly have observed is the fact quoted by several 

 writers that, although most pupae of the Lycaenidae belong to the succincti, 

 there are some which are only fastened to the cremaster, in a hanging or 

 lying position without a girdle thread. 



In certain species such as Jolaus Longinus F. (PI. XXVI, 148(1') in which the 

 pupa bends away some distance from the twig or leaf to which it is attached, 

 this is certainly the case, but it is more doubtful, whether in other pupae ot 

 more usual form and which hang in the ordinary way along twigs and leaves, 

 the girdle thread is perhaps also absent. In that of Awblypodia Narada Horsf. 

 I could not discover one even after careful search ; this pupa is certainly of a 

 particularly massive form, but Jacobson notes the same of the pupa of the 

 very ordinary form of Hypolycaena Etolus F. of which he gives an illustration. 

 Seeing that there is no doubt that it is absent in the first- named species it may 

 be assumed that amongst the Lycaenidae the evolutionary process, discussed 

 in my second introduction, which causes the succincti to change into suspensi, 

 is working in these species ; it is therefore by no means improbable, that the 

 same process is going on in other Lycaenidae, and considering the extremely 

 unequal-rate of progress peculiar to all evolutionaty processes, which we have 

 frequently insisted upon, that this is only the case in a few species. But it is of 

 importance, that accurate observations may be made on this point ; it would 

 form another very clear example of the way in which such evolutionary processes 

 develop, and of the great inequality which governs them. This must be done, 

 however, with great caution ; I therefore consider it desirable to make the following 

 remarks upon the subject. 



