Imago sentence example
It may bite and devour solid food, while the imago sucks liquids.
In the Cyclorrhapha on the other hand, in which the actual pupa is concealed within the hardened larval skin, the imago escapes through a circular orifice formed by pushing off or through the head end of the puparium.
It may eat roots or refuse, while the imago lives on leaves and flowers.
As the life-conditions and feedinghabits of the larva and imago become constantly more divergent, the appearance of the wing-rudiments would be postponed to the pre-imaginal instar, and that instar would become predominantly passive.
The mature dragon-fly nymph, for example, makes its way out of the water in which the early stages have been passed and, clinging to some water-plant, undergoes the final ecdysis that the imago may emerge into the air.Advertisement
Only a brief reference can be made here to the fascinating subject of the life-relations of the larva, nymph and pupa, as compared with those of the imago.
A common result of metamorphosis is that the larva and imago differ markedly in their habitat and mode of feeding.
The larva may be aquatic, or subterranean, or a burrower in wood, while the imago is aerial.
A marked disproportion between the life-term of larva and imago is common; the former often lives for months or years, while the latter only survives for weeks or days or hours.
In several recent attempts to group the orders into sub-classes, stress has been laid upon a few characters in the imago.Advertisement
Mandibles present in pupa, vestigial in imago; maxillae suctorial without specialization; first maxillae with lacinia, galea and palp. Prothorax small.
Mandibles absent in imago, very exceptionally present in pupa; first maxillae nearly always without laciniae and often without palps, or only with vestigial palps, their galeae elongated and grooved inwardly so as to form a sucking trunk.
Cuticle of pupa or puparium splitting longitudinally down the back, to allow escape of imago.
Fragmentary as the records are, they show that the Exopterygota preceded the Endopterygota in the evolution of the class, and that among the Endopterygota those orders in which the greatest difference exists between imago and larva - the Lepidoptera, Diptera and Hymenoptera - were the latest to take their rise.
As shown by the number and variety of species, the Orthoptera are the most dominant order of this group. Eminently terrestrial in habit, the differentiation of their fore-wings and hindwings can be traced from Carboniferous, isopteroid ancestors through intermediate Mesozoic forms. The Plecoptera resemble the Ephemeroptera and Odonata in the aquatic habits of their larvae, and by the occasional presence of tufted thoracic gills in the imago exhibit an aquatic character unknown in any other winged insects.Advertisement
The Neuroptera, with their similar foreand hind-wings and their campodeiform larvae, seem to stand nearest to the presumed isopteroid ancestry, but the imago and larva are often specialized.
And thus perfection of structure and instinct in the imago has been accompanied by degradation in the larva, and by an increase in the extent of transformation and in the degree of reconstruction before and during the pupal stage.
That on geography is particularly good, and is interesting as having been read by Columbus, who lighted on it in Petrus de Alliaco's Imago Mundi, and was strongly influenced by its reasoning.
The head is rather large, and is furnished at first with five simple eyes of nearly equal size; but as it increases in size the homologues of the facetted eyes of the imago become larger, whereas those equivalent to the ocelli remain small.
Reference has been made above to the possibility that the Roman imago of an ancestor actually embodied his ghost, at least on solemn occasions.Advertisement
The size of the imago on the focal plane is always equal to its actual size, and is independent of the distance of the object from the plane focused for.
The 5th larval instar, is followed by the winged imago stage which are 3mm long and brown-black in color.
A natural system must take into account the nature of the larva and of the metamorphosis in conjunction with the general characters of the imago.
As regards growth after hatching, all beetles undergo a "complete" metamorphosis, the wing-rudiments developing beneath the cuticle throughout the larval stages, and a resting pupal stage intervening between the last larval instal1 and the imago.
On the other hand, we find in the vast majority of the Hexapoda a very marked difference between the perfect insect (imago) and the young animal when newly hatched and for some time after hatching.Advertisement
After a prolonged aquatic larval and nymphal life-history, the winged insect appears as a sub-imago, whence, after the casting of a delicate cuticle, the true imago emerges.
If we admit that the larva has, in the phylogeny of insects, gradually diverged from the imago, and if we recollect that in the ontogeny the larva has always to become the imago (and of course still does so) notwithstanding the increased difficulty of the transformation, we cannot but recognize that a period of helplessness in which the transformation may take place is to be expected.
Moreover, in many insects with imperfect metamorphosis the change from larva or (as the later stage of the larva is called in these cases) nymph to imago is about as great as the corresponding change in the Holometabola, as the student will recognize if he recalls the histories of Ephemeridae, Odonata and male Coccidae.
They are abundantly distinct from the Neuroptera and Mecaptera, through the absence of mandibles in the imago, the maxillae - both pairs of which possess the typical inner and outer lobes and jointed palps - forming a suctorial apparatus.
Thus the reflection of a person in a mirror is known as his "image"; in popular usage one person is similarly described as "the very image" of another; so in entomology the term is applied in its Latin form imago to an insect which, having passed through its larval stages, has achieved its full typical development.
The insect, which may have become an imago with the Gordian larva still in it, is then eaten by a carnivorous insect or by a fish, and the contained Gordian larva becomes elongate and mature in its second host.
Before reviewing the history of these discoveries, it is desirable to say a few words of the characters of the axolotl (larval form) and of the Amblystoma (perfect or imago form).
The transformations from the larval state are completed within the gall, out of which the imago, or perfect insect, tunnels its way, - usually in autumn, though sometimes, as has been observed of some individuals of Cynips Kollari, after hibernation.
The Sialidae or alder-flies (q.v.) differ from other Neuroptera in the jaws of the larva - which is aquatic, breathing by paired, jointed abdominal gills - resembling those of the imago, and being adapted for the mastication of solid food.
His fundamental physical maxims are matter and force; the latter he calls virtus, species, imago agentis, and by numberless other names.