APPENDIX 317 



IV. PRESERVATION OF INSECTS 



Place about one hundred grains of potassium cyanide, broken 

 up into small pieces in a large-mouthed bottle, add water to the 

 depth of half an inch, then add plaster of Paris until a dry cake 

 is formed. Wipe out with a cloth the dry plaster adhering to the 

 sides of the bottle. After the bottle has stood loosely corked for 

 an hour, it is ready for use. 



Any insects placed in this poison bottle will die at once. They 

 may be pinned in cigar boxes, or may be preserved in paper enve- 

 lopes for future use. Always keep your poison bottle tightly 

 corked, the cyanide fumes are very poisonous. Children should 

 not prepare the poison bottle, but they can safely use it. In order 

 to make the legs and wings of dried insects again pliable, place 

 the insects in a tin pail, put a piece of moist blotting paper in it, 

 and keep the pail closed for about half a day. 



V. AQUARIUMS 



Common butter jars, glass fruit jars, and electric battery jars, 

 and almost any kind of stone and glass vessels are suitable for small 

 aquariums. Place a few stones, pebbles, and some clean gravel on 

 the bottom. Add a few small water plants, such as the little float- 

 ing duckweeds, tufts of the green threadlike algae, bits of water- 

 pest, etc. Do not place too many plants nor too many animals in 

 one aquarium. Experience must teach you what animals can be 

 placed in the same aquarium without eating one another. Min- 

 nows, crabs, snails, all kinds of aquatic insects, tadpoles, small 

 water plants, can be kept in an aquarium. Minnows and tadpoles 

 eat crumbs of wheat bread or goldfish food ; crabs, water beetles, 

 and a few other insects will eat earthworms, bits of raw meat, flies, 

 etc. Some animals will feed on the minute plants and animals in 

 the aquarium. Feed your animals every other day in summer and 

 every third or fourth day in winter, but give them no more than 

 they will eat. Let little or no direct sunlight fall into the 

 aquarium, keep the water fresh, avoid too great changes of tempera- 

 ture when you change the water. Aquariums with winged insepts 

 must be covered with gauze to prevent the insects from flying out. 



See MialL Aquatic Insects. The Macmillan Company. 



