Nymphalidae

“ Now if we could safely raise Apatura and Nymphalis into a distinct family—an arrangement which in the estimation of Staudinger182 is correct—439and if this were interpolated between the Satyridæ and Nymphalidæ, such an arrangement could only be based on the larval structure, and that of the imagines would thus remain unconsidered, since no other common characters can be found for these two genera than those which they possess in common with the other Nymphalideous genera. ”

“ Uneatable larvae, on the other hand, comprise all that are of conspicuous colours and are hairy or spiny. But with butterflies there is no such simplicity of contrast. The eatable butterflies comprise not only brown or white species, but hundreds of Nymphalidae, Papilionidae, Lycaenidae, etc., which are gaily coloured and of an immense variety of patterns. The colours and patterns of the inedible kinds are also greatly varied, while they are often equally gay ”

“ How to strip off the skin and much more the legs by which the creature is suspended without losing its hold, and at the same time to securely fasten the chrysalis, is a problem that would seem impossible to solve; and yet this little insect accomplishes it unerringly when to fail would be certain destruction. And not this species only, but the larvae of all butterflies which form suspended chrysalids, embracing the whole of the great family of Nymphalidae, that is, a large proportion of all the existing species of butterflies, undergo a similar transformation. ”

“ Such facts of distribution clearly show that though the Nymphalidae have attained a high degree of specialization among the Lepidoptera, some of their genera have a history which goes back to a time when the distribution of land and water on the earth’s surface must have been very different from what it is to-day. ”

“ Nymphalidæ, the largest, containing between four and five thousand species. They have a relatively simple type of coloration, and are interesting because of their disposition to mimic other species. They are distasteful to birds. They include the red admiral, the tortoise-shells, the peacock, and so on, as well as the fritillaries and the purple emperor. In it are also included the remarkable leaf butterflies in which the under surface, in shape, color and markings, closely resemble a dead leaf, while the upper surface is brightly colored. On alighting only the under surface is visible. ”

“ By the establishment, however, of the genus Morpho, comprising the insect figured by Drury, the difficulty is obviated, and as the species is universally known under the name of Laertes, it does not appear requisite to adopt the name of Epistrophus.
NYMPHALIS (CATAGRAMMA) HYDASPES.
Plate XV. fig. 2, 3.
Order: Lepidoptera. Section: Diurna. Family: Nymphalidæ, Swains. Genus. Nymphalis, Latr. God. Papilio (Nymphalis) , Fabr. Subgenus: Catagramma, Boisduval.
Nymphalis (Catagramma) Hydaspes. Alis subdentatis, nigris, basi suprà nitidè cyaneis, anticis utrinque fasciâ chermesinâ abbreviatâ ”

“ Nor does the nymph which succeeds this tertiary larva present any peculiarity: it is the perfect insect in swaddling-bands, yellowish white, with its various external members, clear as crystal, displayed under the abdomen. A few weeks elapse, during which the nymph partly dons the livery of the adult state; and, in about a month, the insect moults for a last time, in the usual manner, in order to attain its final form. The wing-cases are now of a uniform yellowish white, as are the wings, the abdomen and the greater part of the legs; very nearly all the rest of the body is of a glossy black. ”

“ The newly-hatched insect resembles generally its parent, except that it has no wings. Wing-rudiments appear, however, in an early instar as visible outgrowths on the thoracic segments, and become larger after each moult. All through its various stages the immature insect—nymph as it is called—lives in the same kind of situations and on the same kind of food as its parent, and it is all along active and lively, undergoing no resting period like the pupal stage in the transformation of the butterfly. ”

“ Eaton in his elaborate work on the Ephemeridæ employs the term nymph to designate all the aquatic or early stages in the development of the young after hatching, and he urges that the old-fashioned usage of larva and pupa seem scarcely worth retention. “Nymphs are young which live an active life, quitting the egg at a tolerably advanced stage of morphological development and having the mouth-parts formed after the same main type of construction as those of the adult insect.” ”

“ When the little worms are about four or five days old, and have grown so large and fat as to fill their cells, the nurses seal them up with a brown cover of a conical form. No sooner does the larva find himself shut in, than he begins to work up and down, and to wind around himself fine silky threads, which he draws in two strands from the middle part of his under lip. Round and round he goes, for he knows what is to be done; nor does he stop till he has woven about himself a thin pod or pellicle, just the size of the cell. In this condition, the creature is called a nymph or pupa. ”

“ The metamorphosis is also peculiar; the larva does not differ greatly in appearance from the adult, and has similar mouth-organs and food-habits. The wings are developed outside the body at the sides, and appear first, according to Heeger, after the third moult. The nymph-condition is like that of a pupa inasmuch as no nourishment is taken, and the parts of the body are enclosed in a skin: in some species there is power of movement to a slight degree, but other species are quite motionless. In some cases the body is entirely bright red, though subsequently there is no trace of this colour. ”

“ I do not know just how fast they grow, but presume they become full grown in a year. During the earlier period of their existence they have no wings; they are then in what the naturalists call the nymph state. Their appearance just before they become adult is represented in Fig. 2. It will be seen that they have no Fig. 2.—Last Stage of nymph. wings, but otherwise they very much resemble the full-grown bugs. Finally, the skin splits open along the middle of the back, and the insect crawls out of its old skin clothed in a new one which is provided with wings. ”

“ Among the insects of incomplete metamorphosis, the nympha is but little different from the larva, and molts and is fed in the same way. Insects of complete metamorphosis act very differently: the larva becomes stationary and ceases to take food; the skin becomes like parchment, and slight movements of the abdominal rings, when they are touched, are the only signs of life. Yet, from the beginning of the transformation, on the seemingly half-dead being, appear distinctly, although masked by a thick veil, the antennæ, wings, and legs. These organs are symmetrically folded Fig. ”

“ Under conditions allowing about half the normal food supply the average nymphal life was from 116.9 to 139 days. Nymphs starved from birth lived up to 42 days. We have kept unfed nymphs, of the first stage, alive in a bottle for 75 days. The interesting fact was brought out that under these conditions of minimum food supply there were sometimes six molts instead of the normal number.
The adults are remarkable for their longevity, a factor which is of importance in considering the spread of the insect and methods of control. ”

“ The nymph or pupa does not differ from the larva, except in bearing on the back a pair of rudimentary wings, enclosed in a kind of sheath. The larvæ and pupa are, of course, incapable of flight, but the mature insect springs into the air with great facility, and expanding its capacious wings, can sustain itself for a considerable time. In ordinary cases, they traverse but short spaces at a time; but when any change of place becomes requisite, they are able, like their relatives the locusts, to fly both high and far. ”

“ By some feeling of impending change the rnature nymph, waiting in its chamber, knows when the time of transformation is at hand. Somehow nature regulates the event so that it will happen in the evening, but, once the hour has come, no time is to be lost. The nymph must break out of its cell, tind a suitable molting site and one in accord with the traditions of its race, and there fix itself by a tirm grip of the tarsal claws. ”

“ Development.—In most Hemiptera the young insect (fig. 3) resembles its parents except for the absence of wings, and is active through all stages of its growth. In all Hemiptera the wing-rudiments develop externally on the nymphal cuticle, but in some families—the cicads for example—the young insect (fig. 10) is a larva differing markedly in form from its parent, and adapted for a different mode of life, while the nymph before the final moult is sluggish and inactive. In the male Coccidae (Scale-insects) the nymph (fig. 4) remains passive and takes no food. ”

“ This pupa acts just as the larva, crawls up plants and waits to regain the host. After a time the nymphs, having gorged themselves with blood, fall off and remain on the ground for nearly three months; they then moult and become adult males and females. In about ten days they assume their normal colour and regain the host afresh; the female gradually swells until she attains that large inflated form so characteristic of ticks. The male does not swell, but nevertheless feeds upon the host and fertilizes the female. ”

“ Nymphs repeat the behaviour of the larvae, and finally moult into the adult, showing the generative orifice, which is the mark of maturity. The adult secures a host in the same way as the young. Both sexes feed upon blood; whereas the male alters but little in appearance, the female becomes enormously distended.
From the foregoing epitome which applies to many species, Rhipicephalus appendiculatus for example, it is evident that every individual tick has to find a host on three occasions, namely, as larva, nymph and adult. In R. bursa, however, the moult that ”

“ Before taking the evidence of the huntress, let us note that the grub employs its anal pimple to move along with. Too short in the legs, it is a sort of cripple using its inflated stern as a lever. Another fact, whose interest will appear at the proper time, is that, at the moment of the metamorphosis, the larva fastens itself by the anus to a poplar-leaf. The larval skin is pushed back while it remains clinging; and the nymph appears half-sheathed in this slough. The nymph in its turn splits; the perfect insect releases itself ”

“ The Nymphalides include upwards of 150 genera and 2000 species. The divisions having smooth larvae are separated by Kirby [220] and others as a distinct sub-family (Apaturides) . In Britain, as in most other parts of the world, Nymphalides is the predominant group of butterflies. We have eighteen species, among which are included the Fritillaries, Admirals, Purple Emperor, and the various Vanessa—Peacock, Camberwell Beauty, Red Admiral, Tortoise-shells, and Painted Lady. All have spined caterpillars except the Emperor. ”

“ The perfect insect itself, during the time that it is enclosed in the shell, cannot regain it, for lack of the requisite flexibility. This total absence of movement in the tertiary larva, when a few days old, and also in the nymph, together with the smallness of the space left free in the shell, would necessarily lead to the conviction, if we had not witnessed the first moments of the tertiary larva, that it is absolutely impossible for the creature to turn right round. ”

“ Small insects have, as a rule, shorter lives than large ones; those whose larvae devour highly nutritive food generally develop more quickly than those which have to live on dry, poor, substances; life-cycles follow one another most rapidly in summer weather when temperature is high and food plentiful.
In early chapters we have already noticed the long aquatic life of the larva and nymph of a dragon-fly, relatively a large insect, and the rapid multiplication of the repeated summer broods of virgin aphids (p. 18) . ”

“ A leg in formation is not more clearly declared than the horn on the corselet or those on the forehead.
Can time be lacking for the thoracic growth to organize itself into a stiff and lasting appendage? The evolution of the nymph is swift; the insect is perfect in a few weeks. Could it not be that, though this brief space suffice to promote the maturity of the horns on the forehead, the thoracic horn requires a longer time to ripen? Let us prolong the nymphal period artificially and give the germ time to develop itself. ”

“ Once out of the door no time is lost in discarding the encumbering garment, but it is never shed in the nest under normal conditions. If, however, the nest is cut open and the hatching nymph finds itself in a free, open space, the embryonic sheath is cast off immediately, often while the posterior end of the insect's body is still in the
egg, so that the skin may be left sticking in the open end of the shell. ”

“ The eggs are deposited in the soil, ten to twenty thousand eggs in all being laid by one female. The larvae climb neighbouring plants and seize passing animals. After the third day of attachment they begin to distend, and they generally fall off, fully distended, on the sixth day, immediately seeking a place of concealment, where they become torpid. Under natural conditions the nymph does not emerge for at least eleven weeks, and then it behaves in the same way as the larva, again attaching itself to an animal for six days. ”