FoodNet

Handbook of domestic science and household arts for use in elementary schools

1900

Page 157

Presented as published in 1900. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
After a while, the exact length of time governed largely by conditions of food and warmth, the larva encloses itself in a case or sac made either from new materials foreign to the body, or of the dried and hardened skin of the larva itself. This is the pupa, called chrysalis in the butterfly and nymph in the honey-bee. No food is now taken, and there is no movement except slight muscular contractions when the pupa is disturbed. At last the pupal period is past, and out from the case comes the imago or full-grown, perfect insect, — at first weak and trembling, but rapidly becoming used to its new body and new conditions of life. In cases of direct metamorphosis the young differ very little from the adult except in size, the changes being so gradual that to the casual observer they are unnoticed. The most obvious difference in some cases is the presence of wings in the pupa and imago where they were absent in the larva. All stages feed. Many adults live only a few days after emerging from the pupa. They reproduce their kind and die. The time intervening between the egg and adult stages varies from a few days with many insects to seventeen years with the Cicada. Insects have bodies made of three segments, which may be so nearly united that they are distinguished with diffi- culty, or they may be plainly shown as in the wasps and ants. These three segments are again divided into rings, the normal number being thirteen. It is seldom that this number can readily be determined because two or more are often consolidated. The first segment, or the head, bears the usual appendages, eyes, antennae, and mouth parts ; the middle, or thorax, bears 324 HANDBOOK OF DOMESTIC SCIENCE the legs and wings, if tlie latter are present; the last, or abdomen, may or may not bear certain appendages for pro- tection, for aids in locomotion or for digging. The typical insect has three pairs of legs and two pairs of wings. Both pairs of wings may be membranous and flexible, or the upper or front pair hardened into wing covers as in the beetles. The segments are united by flexible joints which aid greatly in the rapid movements characteristic of most insects. Not alone the body, but also the appendages are ringed or jointed. The entire structure shows admirable adaptability to the conditions under which insect life exists. Insects take in air through small slits or holes, called spiracles, on each side of the abdomen. Anything which partly or completely fills these spiracles stops respiration and stupefies or smothers the insect. Hence the effect of powders, oil, etc. The antennae, preeminently, are organs of touch and in many cases are extremely long and sensitive, enabling their possessors to be warned of impending danger or disagree- able conditions long before actual harm is done. Some insects show an acute sense of smell, but just what parts respond to this stimulus is not known. The organs of hearing are sometimes at the bases of the antennae, and sometimes on the wings. Some insects show extreme sensibility to sound.