NOTES ON BlII'TEKKr.Y I'lH'^, ETC. 149 



SO open after dehiscence, that if not actually movable, it can only 

 recently have lost its mol)ility. 



These Micro-characters, together with the larval prolegs pointing to 

 Hepialus as a })0S8il)le ancestor, lead one to ask whether there may be 

 any intermediate forms that mark the steps by the way. Hepialm is 

 now often instanced as a very archaic form, even as the possible 

 ancestor of everything ; Hepialm is, however, a terminal form ; that is, 

 it is at the end of its line of evolution and has no descendants. This is 

 tolerably clear from its minute antennae, but especially from the 

 circumstance, remarkable in so early a form (indeed it is the only 

 instance amongst unquestionable " Micros "), that the male pujia has 

 the 7th segment fixed. 



The real ancestor that is intended, when Hepialus is referred to, is 

 the common ancestor of Hepinhis, Cossus, &c. Hepialus retains sundry 

 archaic featui'es of this common ancestor more persistently than Cosmn, 

 &c. Although it is a little outside the scope of this paper, yet it is of 

 interest to note that these earliest forms had great variability in 

 respect of antenna?. We find plumose, or at least strongly pectinated, 

 antennje in some of the earlier Cossids ; minute antennae in Hepialus ; 

 very long ones in Adela. The latter is a good instance of a similar 

 development separately attained ; certain Trichoptera have very 

 similar antennje, and we find the connecting link in Micropteryx which 

 has ordinary antennjB, but at the same time possesses the pupal jaws of 

 the TrichoiDtera and the ovipositing knives of Adela. 



Now it was somewhere here, amongst these forms with variable 

 antennae, that the first trace of butterflies with their clubbed antennte 

 ap^jeared, and some little distance along the road there branched off, 

 as a record thereof, the Sesiidae. These latter are unmistakeably 

 " Micros," not, indeed, very far removed from Hepialus and Cossus, 

 but they have fairly clubbed antennae. Some considerable distance 

 further on we have Castuia, its larva still an internal feeder, and its 

 pupa * still of a Cos.sHs-like " Micro " character, but its imagines so 

 very Hesperid-like that they have by some authorities been placed 

 with the butterflies. There are other families that are possibly 

 appendages of this line of evolution, but I know so little about them, and 

 especially about their pupaj, that it is prudent to say nothing further 

 about them at present. Clubbed antenna are found in Sphinges and 

 in Zy<jaena ; in both cases they appear to have been acquired 

 independently of the butterfly stirps, and of each other. This circum- 

 stance seems to lend additional force to the idea that clubbed antennte 

 are in some way specially useful to diurnal species. 



To sum u}) the points in this paper. My chief aim has been to call 

 attention to the study of pupte, and especially those of butterflies from 

 a broader and more general point of view, and to bring to bear on 

 them the general i)rinciples of jmpal evolution that were suggested by 

 my study of the Hetekoceua. The special facts brought out concern- 

 ing butterfly ])up£e are to be taken as largely preliminary and tenta- 

 tive, l)ut it is to be noticed that broadly, and even in some detail, the 

 relationship of the different families to each other suggested, 

 agrees with the ordinary classification. The greatest change of views 

 which appears to be demanded is in relation to the position of the 

 Lyc^nids, which should no longer be regarded as in any way inter- 



• I am aorry that I have to depend on figures for my knowledge of these. 



