1900. ] GROTE—THE DESCENT OF THE PIERIDS. 23 
approximately outlined. But the characters used as generic are 
subject to constant modification and this from the total surround- 
ing. And for larva, pupa and imago the exfourage is quite distinct 
and as for different animals. It is this want of correspondence 
which shows itself upon occasion, together with the baffling fea- 
tures of convergence which makes the task of the zodlogist in un- 
raveling phylogeny so extremely difficult. The classificatory strain 
put upon the features of specialization, as for instance by Dr. 
Karsch’s system based upon the larval feet, or Dr. Dyar’s founda- 
tion of the family Apatelidze, is greater than they can bear. 
My conclusion is, that, there being no homology between the 
specializations of the different stages in the Lepidoptera, there is 
also no correspondence.? It may be, in certain cases, that all three 
show marked specializations after their differing fashion, but there 
exists no necessity that they should do so. One specialization does 
not arise out of another. ‘The very unusual larva of Stauropus pro- 
duces a moth not so different from other Ptilodonts, as for instance 
Heterocampa. ‘To revert to the genus Afpaze/a, from which I drew 
my earliest deductions in this matter, if the curious clubbed or flat- 
tened hairs on the body of the caterpillar of Jocheera alni and 
Juneralis, were found instead on the body of the moth, our critic 
would reproach us with ‘‘ ignorance’’ were we to overlook this generic 
character. A specialization is, however, a generic character, in 
whatever stage it presents itself, and in overlooking this in the 
larva our critic is himself at fault. Jocheera cannot be thrown into 
the common pot of Apate/a without covering over its peculiar 
specialization, and to do this is, to use for once a term I dislike, 
unscientific. A peculiar generic title simply means, that the insect 
possesses some peculiar feature, in whatever stage, that distinguishes 
it from its allies. There is, however, no test for the amount of the 
specialization necessary to support an independent title. ‘To weigh 
the value of the categories, without prejudice, is the test of a capa- 
ble classificator. I am not one of Mr. Butler’s censors for his 
paper on Apafe/a, a paper both suggestive and challenging con- 
1 That variations in color in the preceding stages have no influence on the 
imago seems certain. From the two types of the pupa of Papzlio machagn I have 
reared but one of the butterflies. Oscar Schultz separated aberratively culored 
larvee of the same species, and they all produced normally marked and colored 
specimens. Aside from sexual peculiarities, there is then no neces:ary cor- 
respondence between the stages in this respect. 
