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Show . . ENTOMOLOGY 1 Edited by Prof. E. G. Titus, State Agricultural College, If you do not find here what you want to know, write for it. WHAT IS AN INSECT? E. G. Titus. Someone recently asked me why I did not tell the Dcscrct Farmer readers read-ers "what an insect was." According to fhc definition we usually use, an insect in-sect is any animal possessing a body composed of thr.ee parts, the head, the thorax and the abdomen, six legs and usually one or two pairs of wings. The legs arc fastened to the under side of the thorax and the wings to the upper side. Anyone can get a good idea of an insect in its full grown or -adult stage by axamin-ing axamin-ing a grasshopper (one that can fly); a butterfly, or one of those moths that come in the house at night attracted by the lights; a beetle, one of the hard winged insects that also come to light in the house in the early spring; and the true bug, that is the squash bug, or an aphid (plant-louse). While each of these bugs have the parts slightly different, you will notice no-tice at thtt same time that they arc decidedly similar. The younger stages of insects arc not quite so easy to separate into groups. But with the grasshopper, the squash bug and cabbage aphis the younger stages appear very much like the' adult insect. While man)' other insects appear decidedly unlike their parents the caterpillars, young bocs and wircworms. There is a way of classifying insects in-sects according to their manner of feeding which everyone will find of value. All insects, with some very rare exceptions arc cither biting insects in-sects or sucking insects. There is one very large group of insects which have biting and sucking mouth parts; this is the group to which belong the honey bee, the wasp, the ants and such things. In the class known as biting insects come the grasshoppers, the caterpillars, which are the younger stages of the butterflies or the moths, and all of the beetles. The butterflies and moths are themselves sucking insects. in-sects. The principal .sucking insects with which we are ordinarily bothered are the squash bugs, the aphids, such .13 the green aphis and the cabbage aphis, the bed-bug, the mosquitoes i J and some of the flics. While the mouth parts of all the flics arc fitted for sucking not all arc fitted to pierce through the skin of cither plants or IS animals. The ordinary housefly get'; its food by a way that is usually ' called "lapping it up." while the mos- I quito is possessed of a pair of saws '1 in its mouth with which it cuts a min- utc hole in the skin and pushes its i sucking- tube through, using it as a pump to extract blood if it is feeding on an animal, and sap if it is feeding on a plant. It will be noticed in the j above that most of the insects re- fcrrcd to arc adults. There arc a i number of our injurious and bencfi- cial species that do their best or their worst work in their younger stages. '; It will be well now to tell some- thing about the younger stages of the insects. Most of them hatch from an egg. But there arc some very radical rad-ical exceptions. The female of the San Jose scale never lays eggs, the young always being produced alive. The .same is true of many of the aphids, and with many of the other aphids eggs arc produced but once a year, while all the rest of the year the females, often called "stcm-miothcrs" produce living young of the female sex only. What is known as the larval stage of the insects is that part of their life from the time they lta.tch from the egg or are born until they become adults or pass into a resting stage known as the pupal stage from which the adult later issues. This takes us 'back to another form I of classification which was mentioned j above, those insects which have more or less of the appearance of the adult 1 throughout the younger stages, such as .the cabbage aphis and those insects in-sects which arc so totally different in their young stages that they arc often considered to have no relation to the grown insect. Among those familiar to all of you arc the caterpillar cater-pillar which turns into a butterfly or moth, the wire-worm which later becomes be-comes the snapping-beetle and white grub which makes the uiny-beetle or ; the June-beetles. We will have some more about the . insects, their relations and habits some other time, if you wish it. |