﻿114 CLEMENS' SYNOPSIS OF 



branch between the costal and submedian nervures, the intercostal nervule (i c) . The 

 posterior wings are unprovided with a marginal nervure ; the bristle on the edge of 

 the anterior margin at the base, is regarded as a modification of it. Any modification, 

 or additional nervules, found in the wings of individuals of other families, are easily 

 indicated in the same manner as the foregoing. The European systematists name 

 the branches of the subcostal nervure (see fig. 1), commencing at the tip of the wing, 

 the first, second and third superior nervules; and those of the median, the first, second, 

 third and fourth inferior nervules or veins. The space bounded by the subcostal, 

 median and discal nervures, is the discoidal cell, or simply the disc. For purposes of 

 accurate specific description, I have likewise named the spaces between the nervules 

 as follows : (Fig. 1, 1' to 8') the apical interspace, post-apical, subcosto-inferior, medio 

 superior, central and posterior, the submedian and internal. These terms will be found 

 useful in indicating the exact situation of markings on the wing. 



ORAL APPARATUS . 



The differences in the oral organs, during the embryonic and perfect states of 

 lepidoptera are so marked, that it will be preferable to study them first in the larval 

 condition, and then trace the changes which have taken place at maturity. They 

 are especially interesting in showing the modifications introduced in the same organs 

 of an individual, to adapt the apparatus to special modes of existence. In the larva 

 this apparatus is manducatory, and the development of the several parts of which it 

 consists, has special reference to the necessities of larval life. Although a mere 

 embryo, the larva sustains an independent existence, and must rely on its individual 

 exertions for the maintenance of its life, and defense against its enemies. Its entire 

 energies, are devoted to the assimilation of immense quantities of nutriment to supply 

 the material of organic changes ; it is, indeed, an eating machine, the assimilative and 

 digestive system being greatly in preponderance. Its special senses and instinctive 

 endowments have, beyond doubt, marked relations to the dominant necessity of 

 embryonic existence. The former may well be much more restricted or less developed 

 than in the imago, whilst at the same time it would be unphilosophical to suppose, 

 there could be any material difference in the function of the same parts or organs in 

 the two states, however different may be their appearance. All the parts of the 

 embryonic mouth are represented in the imago, but with reference to new conditions 

 of life and in dissimilar proportions. With the addition or assumption of wings, and 

 the complete evolution of the reproductive system, the principal objects connected 

 with life are the propagation of species, and the selection of the appropriate food plants 

 of the young. It will not be maintained, I think, that this latter act is the result of 

 mere instinct independent of sensory endowment ; that the imago is attracted to the 



