| Photo, A. N. Mirzaoff |
| CATERPILLAR BEGINNING ITS COCOON |
In fact the distinction between the two divisions of Lepidoptera is one of convenience rather than of science, for it marks difference of habits rather than of structure. Instead of a naked pupa, that of the moth is inclosed in some sort of envelope called a "cocoon." This may be an earthen cell underground, or a woolly tuft fastened to some such support as the bark of a tree, or a leaf rolled and tied by silken threads into a tube, or a burrow in dead wood, or a paperlike case fastened to a twig; but in every case some special provision is made for the easy emergence of the imago when the time comes for its birth as a moth. The moths themselves do no harm. Their few weeks of life are devoted entirely to mating and putting their eggs in just those places where the larvæ they will never see can have the food proper for them and the best chance for life—a matter of marvelous instincts and adaptations. Few of them, except the hawk moths, eat at all. That is done in the caterpillar stage, when many sorts become destructive of the labor and hopes of the farmer and gardener and orchardist, or make havoc in stores of grain and meal, and in garments of wool and fur, carpets, and cabinets of natural history specimens.
| Photo, A. N. Mirzaoff |
| MOTH AND EGGS |
Most of the moths are small, inconspicuous, grayish or brownish creatures whose markings, very lovely when closely examined, so closely resemble in their mottlings the places where the moths rest during the day, that they are comparatively safe from the birds, monkeys and other enemies that seek to catch and eat them. Some, however, are of large size and brighter hue. Thus the silkworm moths of the Orient (and of our own land) may measure four or five inches across the outstretched wings, as does the cecropia and others that flit about evening lights; and a near relative among us is the exquisite, long-tailed, luna moth, which is pale green with chestnut edgings; many others in this group are almost as "richy bedight" as butterflies. It is these that make the large papery cocoons so easily seen in the fall in trees and bushes.
A remarkable family (Bombycidæ) is that of the hawk moths, which much resemble in shape and action humming birds. They are day flyers, but most active in the morning and evening twilights, and hover on whirring wings before a flower, while with their long, tubular tongues they suck its nectar, for these moths feed as well as do their fat, uprearing, bulldoglike caterpillars, to which they owe another common name for the family—that of sphinx moths. Their pupæ are lodged under, on, or near the ground in a loose cocoon, and are to be recognized by an appendage, curled around like a jug handle, in which lies the chrysalis' long tongue.
FLIES AND THEIR HYGIENIC IMPORTANCE
Flies, scientifically speaking, are only those insects of the order of Diptera, distinguished by having only one pair of fully developed wings. They pass through a complete metamorphosis, and the larva is in all cases a "grub" or "maggot" destitute of legs. It is rarely enclosed in a cocoon but lies buried in the ground, floats in the water, or is protected by the last larval skin which, separating from the pupa skin, remains around it as a hard case. Flies and their larvæ live in the most diverse manner. Some flies attack backboned animals and suck their blood, some prey on smaller insects, some suck honey, and some find their food in decaying animal and vegetable matter. A large number of dipterous larvæ eat refuse, many feed inside growing vegetable tissues, and some prey, or are parasitic, on other insects. More than 10,000 species of true flies have already been named in the United States alone. The order contains all the different species and varieties of fleas, mosquitoes, sand flies, gnats, midges and gall flies. Then come the blood-sucking gadflies, and half a dozen families allied to them; the scavenging syrphus flies, the bots that trouble cattle, the house flies and stable flies of deservedly bad repute; and, lastly, the horseflies, bee parasites, and botflies. The popular interest in these insects is confined to the flies of our houses and stables, and to the mosquitoes. In fact it is in the relation that the flies mentioned, and some others, bear to public health and comfort, that this group of insects is important at all to any but the special student.