Moths of the Limberlost: A Book About Limberlost Cabin

by Gene Stratton-Porter

If the moth does not feed, the mouth parts are scarcely developed. If a feeder, it has a long tongue that can be coiled in a cleft in the face between the palpi, which Packard thinks were originally the feelers. This tongue is formed of two grooved parts so fastened together as to make a tube through which it takes flower and fruit nectar and the juices of decaying animal matter.

What are thought by some to be small organs of touch lie on either side the face, but the exact use of these is yet under discussion, It is wofully difficult to learn some of these things.

In my experience the antennae, are the most sensitive, and therefore the most important organs of the head—to me. In the Attacine group these stand out like delicately cut tiny fern fronds or feathers, always being broader and more prominent on the male. Other families are very similar and again they differ widely. You will find moths having pointed hair-like antennae; others heaviest at the tip in club shape, or they may be of even proportion but flat, or round, or a feathered shaft so fine as to be unnoticed as it lies pressed against the face. Some writers say the antennae are the seat of scent, touch, and hearing. I had not thought nature so impoverished in evolving her forms as to overwork one delicate little organ for three distinct purposes. The antennae are situated close where the nose is, in almost every form of life, and I would prefer to believe that they are the organs of scent and feeling. I know a moth suffers most over any injury to them; but one takes flight no quicker or more precipitately at a touch on the antennae than on the head, wing, leg, or abdomen.

We are safe in laying down a law that antennae are homologous organs and used for identical purposes on all forms of life carrying them. The short antennae of grasshoppers appear to be organs of scent. The long hair-fine ones of katydids and crickets may be also, but repeatedly I have seen these used to explore the way ahead over leaves and limbs, the insect feeling its path and stepping where a touch assures it there is safe footing. Katydids, crickets, and grasshoppers all have antennae, and all of these have ears definitely located; hence their feelers are not for auricular purposes. According to my logic those of the moth cannot be either. I am quite sure that primarily they serve the purpose of a nose, as they are too short in most cases to be of much use as 'feelers,' although that is undoubtedly their secondary office. If this be true, it explains the larger organs ofthe male. The female emerges from winter quarters so weighted with carrying from two to six hundred eggs, that she usually remains and develops where she is. This throws the business of finding her location on the male. He is compelled to take wing and hunt until he discovers her; hence his need of more acute sense of scent and touch. The organ that is used most is the one that develops in the evolution of any form of life.

I can well believe that the antennae are most important to a moth, for a broken one means a spoiled study for me. It starts the moth tremulously shivering, aimlessly beating, crazy, in fact, and there is no hope of it posing for a picture. Doctor Clemens records that Cecropia could neither, walk nor fly, but wheeled in a senseless, manner when deprived of its antennae. This makes me sure that they are the seat of highest sensibility, for I have known in one or two cases of chloroformed moths reviving and without struggle or apparent discomfort, depositing eggs in a circle around them, while impaled to a setting board with a pin thrust through the thorax where it of necessity must have passed through or very close the nervous cord and heart.

The moth is covered completely with silken down like tiny scales, coloured and marked according to species, and so lightly attached that it adheres to the cocoon on emergence and clings to the fingers at the lightest touch. From the examination of specimens I have taken that had disfigured themselves, it appears that a moth rubbed bare of down would seem as if covered with thinly cut, highly polished horn, fastened together in divisions. This is called 'chitine' by scientists.

The thorax bears four wings, and six legs, each having five joints and ending in tiny claws. The wings are many-veined membranous sacs, covered with scales that are coloured according to species and arranged to form characteristic family markings. They are a framework usually of twelve hollow tubes or veins that are so connected with the respiratory organs as to be pneumatic. These tubes support double membranes covered above and below with down. At the bases of the wings lie their nerves. The fore-wings each have a heavy rib running from the base and gradually decreasing to the tip. This is called the costa. Its purpose is to bear the brunt of air-pressure in flight. On account of being compelled to fly so much more than the females, the back wings of the males of many species have developed a secondary rib that fits under and supports the front, also causing both to work together with the same impulse to flight. A stiff bunch of bristles serves the same purpose in most females, while some have a lobe extending from the fore-wing. As long as the costa remains unbroken to preserve balance, a moth that has become entangled in bushes or suffered rough treatment from birds can fly with badly damaged wing surfaces.

In some species, notably the Attacine group and all non-feeding, night-flying moths, the legs are short, closely covered with long down of the most delicate colours of the moth, and sometimes decorated with different shades. Luna has beautiful lavender legs, Imperialis yellow, and Regalis red-brown. The day-flying, feeding group have longer, slenderer legs, covered with shorter down, and carry more elaborate markings. This provision is to enable them to cling firmly to flower or twig while feeding, to help them to lift the body higher, and walk dextrously in searching for food. It is also noticeable that these moths have, for their size, comparatively much longer, slenderer wings than the non-feeders, and they can turn them back and fold them together in the fly position, thus enabling them to force their way into nectar-bearing flowers of trumpet shape.

The abdomen is velvet soft to the touch, and divided into rings called segments, these being so joined that this member can be turned and twisted at will. In all cases the last ring contains the sex organs. The large abdomen of the female carries several hundred embryo eggs, and that of the male the seminal fluid.

Much has been written of moths being able to produce odours that attract the sexes, and that are so objectionable as to protect them from birds, mice, and bats. Some believe there are scent glands in a few species under the wing scales. I have critically examined scores of wings as to colour markings, but never noticed or smelled these. On some, tufts of bristlelike hairs can be thrust out, that give a discernible odour; but that this carries any distance or is a large factor in attracting the sexes I do not believe so firmly, after years of practical experience, as I did in the days when I had most of my moth history from books. I have seen this theory confounded so often in practice.