Insect pests of food ; the control of insects in flour mills / [by J. A. Freeman and E. E. Turtle] ; with a foreword by the Director of Infestation Control.
- Great Britain. Ministry of Food
- Date:
- 1947
Licence: Public Domain Mark
Credit: Insect pests of food ; the control of insects in flour mills / [by J. A. Freeman and E. E. Turtle] ; with a foreword by the Director of Infestation Control. Source: Wellcome Collection.
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![Section p LIFE HISTORIES AND HABITS OF INSECTS AND MITES INTRODUCTION There is a lingering fallacy, much less widespread than formerly, that the presence of insects and mites in food is inevitable, due to the belief that they are an inherent part of the food or are “‘ germinated ” in it. If this were so we should be fighting a battle which had been already lost and no amount of application of contro] measures would be of any use. Fortunately insects and mites breed like other animals and the entomologist has yet to find an insect or mite which has been specially created and has not developed from eggs laid by the mother. There are more kinds of insects in the world than of all other kinds of animals, but fortunately only a few of them are pests of stored products. Insects and mites have certain features in common since both belong to the big group called ARTHROPODA, or jointed limbed animals, to which belong also spiders, crabs, lobsters, shrimps, woodlice and barnacles. INSECTS. All adult insects have certain features in common, which enable them to be recognised easily. These features are :— (1) The body consists of three regions called the “head,” “thorax” and ‘ abdomen ”’ respectively. (2) The head bears a pair of ‘“‘antenne”’ or feelers, a pair of large compound eyes and the mouthparts. (3) The thorax bears three pairs of jointed legs. It usually also carries two pairs of wings but these may be reduced to a single pair or sometimes be absent altogether. (4) The abdomen consists of a number of segments or joints and in the adult insect carries no legs. The insect cuticle or skin is hard and horny, and has much the same function as the internal skeleton of the vertebrate, the muscles being connected to the infoldings of the cuticle. Insects breathe air, but this is conducted directly to the tissues by a series of branching tubes, known as “‘ tracheze’’ which lead in from breathing holes, or “ spiracles,” on the sides of the body. Insects have very little control over their temperature, such as have warm blooded animals. ‘They are thus directly affected by changes in the temperature of the air surrounding them and, in common with other living things of similar organisation, live more quickly the higher the tem- perature. ‘here are, however, limits to this phenomenon, and above about 90 deg. I’. they die after a longer or shorter period, so that at 140 deg. F. they are dead in a few minutes. At the lower end of the scale, most insects are immobilised at tem- peratures at or below 40 deg. F. Many of them, however, are capable of withstanding great cold for long periods. All insects lay eggs, which, particularly in the higher groups of insects, do not hatch into individuals like their parents, but into small worm-like beings, known as “‘larve,”’ “grubs”? or “ caterpillars.” The eggs from which these hatch are usually very small, being seldom more than 0.5 millimetres in length. The “larve”’ have no wings and the abdomen is usually proportionately much longer than in the adult. Usually the thorax can only be distinguished from the abdomen by the fact that it carries the jointed legs. Many larve of C2](https://iiif.wellcomecollection.org/image/b32185911_0039.jp2/full/800%2C/0/default.jpg)
