George Vernon Hudson

“ The numerous modifications in the position of the veins and their presence or absence in certain groups can, so far as we are able to see, have had very little effect on the well-being of those insects possessing such modifications. Hence it may fairly be assumed, that these structures have been free from the influence of natural selection for a very lengthened period. It is thus contended that the neuration of a Lepidopterous insect probably reveals more plainly than any other character its true relationship with other species. ”

“ If a nauseous insect were not easily identified it would speedily be destroyed by what Professor Poulton ingeniously terms "experimental tasting"; hence, through the process of natural selection, all nauseous species have become very conspicuously coloured. It may be remarked that warning colours are extremely rare amongst the New Zealand species, and I am not aware of any other example than that already given. ”

“ Other examples might be given amongst exotic Lepidoptera. Thus, many noxious species are closely mimicked by harmless forms which are often far removed from them in real affinity. These cases of adaptive resemblances abound amongst all organisms, and have often deceived experienced naturalists. It is in consequence of the illusive nature of these external resemblances amongst different members of the Lepidoptera, that the structure of the neuration of the wings is now considered of such great importance as a character for purposes of classification. ”

“ In this case it can be seen that if a harmless insect varied in the direction of resembling a formidable or objectionable species it would be a decided advantage to it, and such varieties would tend to be continually preserved and improved, through the operation of natural selection. ”

“ The subject of mimicry has been alluded to here as it is not impossible that some instances of it may yet be discovered in connection with our native Lepidoptera.
Ornamental Colouring.—This class of colouring occurs in many species, especially amongst the butterflies, and is not apparently connected in any way with protection. Darwin supposes that it has arisen through the females of each species always selecting the most beautiful males as mates, hence these alone would leave progeny, and the females themselves would afterwards become beautiful through the effects of inheritance. ”

“ Inheritance.—Many of these variations are inherited—a fact demonstrated by our domestic plants and animals, where man has selected and bred from varieties suitable for his purposes, and has thus produced races in which the variation is permanent. Many of the races of domestic animals differ as much from one another as do some distinct species of wild animals. ”

“ In conjunction with other evidence it would appear to indicate that the Lepidoptera originated from insects with active pupæ. The number of free or movable segments of pupæ varies considerably in different groups and genera, and by some modern authors it is regarded as a character of much importance in the framing of their classifications. The various organs of the perfect insect are distinctly marked out on the otherwise uniform integument of the pupa. In some groups, notably the Micropterygina, these organs are much more distinctly indicated than in others. ”

“ The function of the sucking stomach is to exhaust the air in the throat and proboscis, and thus to cause the ascent of the fluids into the stomach when the insect is feeding.
III.—ORIGIN OF SPECIES.
The theory of the origin of species as propounded by Darwin may be thus very briefly summarised:—
Variation.—No two organisms are exactly alike; there is always some variation from the parent form, in some cases very slight, in others considerable. ”

“ They are usually regarded as organs of touch, but their true function does not seem to be properly understood. In the Lepidoptera they appear to protect the proboscis, which, when out of use, is always coiled up in a spiral between them. The labrum and mandibles can only be seen by removing the large labial palpi.
THE THORAX
carries the organs of locomotion, which consist of two pairs of wings attached to its sides, and three pairs of legs attached beneath, a pair belonging to each of the three segments of which the thorax is composed. ”

“ No new organ can be produced except as a modification of some previously existing structure.
" (2) A lost organ cannot be regained.
" (3) A rudimentary organ is rarely redeveloped."— (Meyrick.)
C. The greatest care is necessary to avoid being misled by adaptive characters, i.e., characters which are very important to the welfare of the species, and hence much modified through the agency of natural selection. ”

“ A familiar instance of superficial resemblance, due to the presence of similar adaptive characters, may be observed in fishes and whales, where two groups of animals with but little real relationship have, through living under similar conditions, become extremely like each other in external appearance. ”

“ They supply the silken threads which are employed by most larvæ in constructing their cocoons, and which also serve in cases of danger as a rapid means of retreat. Many larvæ, which live on shrubs and trees, suddenly lower themselves to the ground by means of one of these silken threads, and thus often escape being devoured by insectivorous animals. ”

“ Some workers prefer to put a drop of benzine on the spot, which renders it temporarily transparent; the effect is short-lived, as the benzine evaporates rapidly, and the cilia (if long) are liable to be damaged by this method. ”

“ This principle Darwin has termed Sexual Selection, and has discussed it in great detail in his work on the 'Descent of Man.' The fact, that amongst birds and butterflies the males are nearly always the most brilliantly coloured and the most beautiful, together with an immense mass of other evidence, tends, I think, to entirely support Darwin's theory, although it should be mentioned that several eminent naturalists, including Mr. ”