soak up an astonishing amount of liquid before becoming visibly wet. That is the secret of this kind of killing jar. If you saturate the plaster in your bottle with a volatile liquid which is poisonous to insects, it will kill your specimens quickly and safely for hours without slopping at all. There are several fluids of which the fumes are lethal to insects but relatively harmless to people, at least in the quantities necessary for entomological collecting. Ether and chloroform are excellent, but expensive. Ethyl acetate is cheaper, and is preferred by some professional collectors. You can get it at the drug store, or from chemical supply houses, which are listed in the classified telephone book. When you order, ask for the technical or commercial grade. The medical quality costs more, and is not necessary. Eight ounces should last you a long time. Carbon tetrachloride, another effective killing fluid, is sold by most drug and department stores as a spot remover, under the name of Carbona, and others. No matter what they call it, the technical name is always somewhere on the label. Carbon tetrachloride leaves the specimens stiffer than do other poisons, but except in the case of butterflies which are to be mounted at once, this does not matter much. Saturate the plaster in your jar at the beginning of every day's collecting. The liquid may be run down the inside of the bottle, or dropped in with a medicine dropper or a spoon. It will be absorbed more quickly if the whole surface of the plaster is not covered with liquid at one time, as this tends to seal in the air, which must come out before the fluid can occupy its space. The damp part of the plaster will be slightly gray, and you can watch the stain spread until it reaches the bottom all around. The bottle is then ready to use. Keep the killing jar tightly closed except when putting in the specimens, or taking them out. Although you should not need it, you might carry a small bottle of extra killing fluid on a long trip. If the bottle is not operating efficiently, a quick sniff will tell you whether or not to re-charge it. But do not sniff too often or too long. The fumes of all those killing fluids make some people ill. If the bottle has been over-loaded with liquid, and the specimens are dampened by it, do not be alarmed. It will dry off without doing any damage. A jar intended for heavy bodied insects may be cushioned with several strips of paper towelling, which absorb the moisture of the specimens, and help to prevent them from clawing and biting one another. A Lepidoptera bottle should contain nothing but moths or butterflies, and not too many of them at once. A killing jar of this kind works rapidly. It will "knock out" most insects in less than a minute, and thoroughly kill them in five. Some species, however, are very hard to kill, and, just to make sure, you had better leave everything in the jar for half an hour. It is very distressing to have a specimen come to life on the pin. A pair of tweezers is very useful for taking insects out of a bottle. For butterflies they are essential, as these cannot be touched with the fingers without ruining their appearance. Slender, pointed tweezers can probably be bought at a drug store, but smooth broad-ended stamp forceps, which you can find in a stamp-collectors shop, are better for butterflies. If possible, mount your specimens on the same day that you catch them. If there is no time for this, put them away between layers of thin glazed cotton or soft paper, in a tight box. The box should be left open in a warm dry place for several days until the insects have dried out thoroughly. Then, before closing, put in a teaspoonful of paradichlorobenzene moth crystals to prevent mold and keep out the carpet beetles. "Para" is sold by drug and ten-cent stores under various trade names, of which di-chloricide is one. The full chemical name is somewhere on the box in small letters. In an emergency, when there is not time or means to make a plaster-bottomed bottle, an acceptable substitute can be thrown together with cotton and blotting paper. Pack the cotton into the bottom of the bottle as tightly as you can, and secure it with a disc of heavy blotting paper, cut to fit the inside of the bottle snugly. Such a jar works exactly like a plaster-bottomed one, but is not effective for so long a time. The cotton wad is apt to be dislodged if the bottle is jolted. The proper methods of mounting insects, and of relaxing those which have been dried unmounted, are discussed in leaflets numbers four and five. 3