may harbor a multitude. Burrowing species make their homes in humus, sand, packed clay, or the sodden mud of river banks and marshes. In the dry dust under porches, or in the shelter of cliffs and the mouths of caves, Ant-lions make their little sand traps. In the depths of caves, perpetual darkness hides a curious insect fauna of its own, a limited but special- ized population which should be investigated when- ever opportunity arises. Most adult insects fly, and when the air is warm enough it swarms with them, especially in the vicinity of flowers. In our northern Spring, the inconspicuous blossoms of shade trees are well attended. All summer long garden and meadow bustle with bees, flies, wasps, and butterflies from dawn till dusk; and, with twilight, the crepuscular and nocturnal forms begin their night's activity. Large numbers of these are attracted to lights, and can be trapped, netted under street lamps, or picked off of window screens. Adults of species which are aquatic when immature may often be taken on the wing above ponds and streams, while predaceous species are frequently found "hawking" along hedgerows, roadsides, and forest paths and clearings. Barnyards, too, are worthy of attention, yielding, especially, biting and parasitic flies, and such species as may feed or breed in filth. Lakes and mud puddles, rivers and ditches, fresh water in any quantity is well provided with aquatic insects. So is the salt water of the tidal zone. Some of the creatures skate upon the surface without wetting their feet. Some dive when alarmed. Some are skillful swimmers, while others creep upon the bottom, bur- row in mud, bore in aquatic plants, or cling tenaciously to the polished stones of swift-running mountain streams. There are insects in arctic waters which are frozen solid a great part of the year, and in thermal springs so hot that few forms of life can endure them. Rainwater caught in footprints, tin cans, hollow trees, and eaves troughs soon swarms with insect larvae. Even a neglected bowl of flowers in your parlor can harbor a generation of mosquitoes. Plants of every size and condition, from the little green algae on the tree trunk to the great tree itself, afford room and board to countless six-legged "guests." Seed, seedling, growing plant, mature, dying, dead, dry, decaying, rotten, and reverted to the earth, plants in all stages support insects of all stages, wherever plants and insects grow. Leaves, flowers, and fruits may be devoured entire or delicately mined from within. Sap and nectar may be sucked, twigs pierced, stems hollowed, pith excavated, bark gnawed, trunks and branches riddled, and roots bored. Most of these activities leave traces by which the astute collector may discover the actors. While looking for them, you will also come across a variety of casual visitors, nocturnal creatures passing the day in a convenient crevice, fleet-winged species resting in the sun, as well as predators and parasites deliberately seeking the more permanent residents. Plant galls amply repay investigation, producing not only the original causative insect, but also parasites and the uninvited guests called inquilines. Since all such creatures are small, and most of them minute, it is necessary to take the galls home and rear their inhabitants in captivity to be perfectly certain of their association. Animals, too, have their hexapodous associates. Mammals, birds, reptiles, and even fish, are subject to the attack of parasites, external and internal. Many of these are specific to a particular host, and a systematic examination of all available animals will reveal a con- siderable assortment. Insects themselves are almost all parasitized by other insects, and there is a great deal of interesting work to be done in establishing their relationships. Dead animals, and even their dry bones, attract a different set of insects seldom to be found elsewhere; flesh flies and carrion beetles among others. And, if you are not too fastidious to look, dung also yields its own unique and numerous inhabitants. Not even Man himself escapes the attention of insects. Some of them simply come for dinner, others take up permanent residence and cannot be evicted without violence. Buildings erected by Man for his own accomodation appeal to insects looking for a good warm place to spend the winter, and some of them like it so well that they stay the year round. All the food gathered and stored by Man for his future sustenance sustains, as well, a numerous hexapodous company. His rugs and clothing, his books and furniture, the very roof over his head and the floor beneath his feet may look like lunch and lodging to one insect or another. In short, there is, for practical purposes, no place collector can look in which an insect may not occur. Some localities are richer than others, and a habitat which is thronged this week may be deserted next, but until you have searched a place thoroughly you cannot be sure whether or not insects are hidden there. When you have collected in any area a long time, you will learn what hours, spots, and atmospheric con- ditions are likely to be most productive. But do not let this knowledge limit your activities. The species aboard in less favorable circumstances may differ from those of the rush-hour crowd. On the other hand, do not ignore a species simply because it is extremely abundant. It may be a strongly seasonal form, available in the adult state for a few days or a few hours only, out of the entire year; or perhaps it is one with a long life-cycle, maturing only at intervals of several years. It could be a very long time before you see the animal again. 2