THE LEPIDOPTERA. 
161 
morphoses appear to eclipse everything else which may have to 
do with the progressive and systematic development. The em- 
bryonic life, or that within the egg, the moults, and the first and 
second metamorphoses, are then the more or less important and 
marked stages in the evolution of the lepidopterous insects. Some 
caterpillars do not assume, either at first or at all, a perfect larval con- 
dition, and then the embryonic stage has been less complete than 
usual. Thus the caterpillars of the Cochliopodidce are legless ; and 
this state of things is not restricted to that genus. In other in- 
stances the larvae, when hatched, present evidences of advanced 
development, and in one genus the pupa appears to be far 
advanced towards the future condition. The extraordinary variety 
of the shape and colour of the caterpillars of the Noctuina , 
and the identity of the moths have been noticed ; but the study 
of the phenomena repays, for it adds to our conception of the 
mysteries of the metamorphosis. 
It is interesting to note the structural relations between those 
Lepidoptera which have a scanty supply of wing scales and the 
Hymenoptera , and to observe the curious mimicry of shape and 
tints which then prevails. 
The metamorphoses of the Lepidoptera may be classified, for 
the sake of convenience, as follows : complete, incomplete, and 
retrograde. The duration of the stages, however, differs, and 
necessitates a second scheme. The metamorphosis takes place 
once in the year, and the eggs remain unhatched until the spring 
— a long embryonic stage — the other stages being short. The 
metamorphosis takes place twice or more in the year, and the 
eggs of the last brood remain through the winter and into spring. 
Here the embryonic stage differs in length. The metamorphosis 
may not be completed in the summer and autumn, and the chry- 
salis lives as such through the winter and into the early summer. 
The caterpillar may hybernate, and the metamorphosis may take 
place early in the year ; or the caterpillar stage may last more 
than a year. It is perfectly evident that closely allied Lepidop- 
tera have different forms of metamorphosis, and that the pheno- 
menon has been acquired in accordance with a law. 
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