DIURNAL LEPIDOPTERA. 3 



ot the Ilesperkljie. and through them of the ITetcrocera, and can 

 confidently assort that, in the preparatory stages, these two faiuilios 

 are as unlike as any of the series. And as to the butterflies them- 

 selves they stand at the two poles. Even 3Ir. Bates says of the 

 PapilionidiC, they are ''quite unconnected with the Ilesperida^, no 

 connecting links between the two families being known." (Jl. of 

 Entoni. 18G1, Dec.) In the imago, some Danainaj and Heliconina3 

 closely resemble species of Papilioninje and of Pierinae, and in any 

 arrangement these four sub-families should stand near each other. 

 But the fact of atrophied fore legs in Danais should no more give it 

 precedence over Papilio than does such atrophy in other orders of 

 insects give pre-eminence to the species subject to this phenomenon, 

 or to the genera and families which contain them. 



I do not believe that one family of the Diurnals has necessarily 

 been evolved from another, and all from the Heterocera, by successive 

 stages, in a direct line, as is implied in the arrangement I object to, 

 but rather tluit, if such development may have sometimes taken place, 

 in other cases families have radiated from a common progenitor, just 

 as a group of species has done. And here and there resemblances 

 between such families must be expected to occur, just as they do 

 occur between the species, in both cases merely because they had 

 a common origin. 



The proposition is enunciated by 3ir. Darwin, that '• distinct species 

 present analogous variations, and a variety of one species often assumes 

 some of the characters of an allied species, or reverts to some of the 

 characters of an early progenitor." And what is true of species is just 

 as true of genera and families. 



Moreover there may be affinities which are so only in appearance, 

 arrived at through - biological necessity," as where the larv;\) of l*ar- 

 nassius protects its chrysalis by a sort of coccoon, after the fashion of 

 certain of the Heterocera, a fact much insisted on by the advocates 

 of the modern arrangement. Now that habit may well have been 

 found uselul in this genus, considering the exposure to which the 

 species are subject, dwelling on lofty nmuntains. treeless, often shrub- 

 less, and storm-i^wept. A u; ked and sus|)ended chrysalis would stand 

 a poor chance of surviving in such a region, and it is well known that 

 the Parnassians alone of the Papilioninac have been able to gain and 

 maintain a foothold in elevated districts. That they have done it is 

 owing to the nece.s.'^ary modification of the habits of the larva), and it is 

 a singular notion that success in such respect should work the degrada- 

 tion of themselves and all their blood relations. 



