[Download] "British Butterflies" by A. M. Stewart # eBook PDF Kindle ePub Free
eBook details
- Title: British Butterflies
- Author : A. M. Stewart
- Release Date : January 01, 2020
- Genre: Nature,Books,Science & Nature,
- Pages : * pages
- Size : 2136 KB
Description
What is the difference between a butterfly and a moth, and how am I to distinguish between them? is a question very often put to the student of insect life—the entomologist.
Butterflies and moths both belong to the Natural Order, Lepidoptera, or scale-winged insects. Butterflies may be distinguished as day flyers, and the moths fly by night. The main physical difference between them appears in the forms of the antennæ, or horns; in the butterflies these organs are club-shaped at the extreme ends. But the antennæ of the various species do not all follow a common pattern. In some the knob is abrupt and much smaller, after the manner of a drum-stick; in others, the thickening commences well down the shaft, and is gradually increased until it very much resembles an Indian club. The antennæ of the moths, on the other hand, show much diversity of form, and in a great many species they are totally different in the male and female. A very common and beautiful form is the feathered, or comblike, antenna; another is long and threadlike, and some show a combination of these two forms; others, again, seem to be striving after the butterfly type, and approach the club shape. It should be noted that not a few moths fly during the day, but it is rare, exceedingly rare, to find a butterfly abroad after sundown. With a little practice in observation, the novice soon learns to distinguish between the two.
The stages of development of butterflies and moths are practically the same: first the egg; next the caterpillar, or larva; then the pupa, or chrysalis; and, lastly, the imago, or perfect insect.
The eggs of the Lepidoptera are surpassingly beautiful. Are they like birds’ eggs? Not at all! In the first place they are too minute for comparison with the larger product of the birds; both in colour and form they more nearly resemble small shells or pearls, as a great many of them are beautifully opalescent, especially when empty. A good hand-lens will reveal a great deal of their beauty, but the low power of an ordinary compound microscope will be necessary to enable you to see all the nice detail of pattern sculptured on their surfaces. Each species of butterfly, or moth, produces eggs of particular shape and ornamentation, so it is quite possible, in most cases, to say to which species an egg belongs. How long the egg may remain unhatched depends a good deal upon which butterfly’s egg it is, the season of the year, and the temperature. Not many butterflies pass the winter in this country in the egg state, that season being usually passed either as a half-fed hibernating caterpillar, or as a chrysalis; and in a few cases it is only the female which passes the winter in some secure retreat, to emerge again in the spring, and then deposit her eggs on the fresh-growing verdure. But, generally speaking, eggs laid during the summer hatch out in from ten to sixteen days. And it is well to be on the lookout for the young larvæ even earlier, if you intend to rear some species in confinement. If you have secured eggs to rear from, watch them from day to day to see if they darken, as they often assume a dark leaden hue immediately before hatching. This is a useful warning, and serves as a hint to have plenty of fresh food ready for the young family about to arrive.
The caterpillars are ravenous eaters; you will not notice this fact particularly at first, because they are then such tiny creatures, but in proportion to their size their eating capacity is enormous. They grow at an exceedingly rapid rate and to such an extent that they literally burst their skins! In a very short time—three or four days—the old skin bursts and out comes Mr. Caterpillar with a brand-new one. And this is the manner of their growth; several times (five or six) this skin-shedding process is repeated. And then the creature prepares for the last and final change before turning into a butterfly.
There are one or two more points I would ask you to notice about our caterpillar ere we pass on to consider his next stage. The legs are generally sixteen in number. There are six true legs, one pair on each of the first three body-segments behind the head; four more pairs near the anal end, and the last segment carries another pair, known as the “anal claspers.” The first six may be said to represent the same legs in the perfect insect. Note also the breathing holes, or spiracles, placed in a row along either side of the larva. The head seems to carry very large eyes, but it does not really do so; the real eyes are very minute, and it requires a good strong pocket-lens to make them out. There are twelve of them all told, and they are not all of equal size. There are six on either side of the mouth, and the three larger ones on each side are not very difficult to find. The mouth is furnished with strong mandibles for biting and chewing food, and also contains the spinneret for the production of the silk used on various occasions. All these details should be carefully noted—the head, the eyes, the breathing spiracles, the mandibles, the fore-legs and claws, and the hind- or pro-legs. Mark the totally different types of feet which terminate these two sets of legs. You will need to use your lens for this observation, and to enable you to see the beautiful structure of the pro-leg foot, it will be necessary for you to examine it through a compound microscope. It is well for the young entomologist to know these more prominent features of a caterpillar’s economy, if for no other reason than to be able to answer the questions that are sure to be put to him on these and many other points.