FIELD AND LABORATORY EXERCISES 



407 



The beetles may be kept off to some extent by the use of fine 

 tobacco dust, ashes or lime mixed with Paris green. The insects 

 are seldom killed by the poison, but they may be somewhat warded 

 off the main crop in this way. 



FIELD AND LABORATORY EXERCISES 



1. Make poison bottles for the collection of insects by using wide mouthed 

 bottles with good stoppers, each bottle about one-half pint in size. Put a 

 piece of potassium cyanide as large as the end joint of a man's thumb in the 

 bottom of each bottle. Cover this with - 



dry plaster of Paris, and then pour in 

 enough water to wet the mass and cover 

 it to a depth of one-quarter of an inch 

 or more. Allow the bottles to stand 

 with the corks in until the plaster has 

 hardened. Then remove the corks, pour 

 off the water and insert a piece of blot- 

 ting paper to absorb the surplus mois- 

 ture. When the bottle has dried out it 

 is ready for use. Cut a piece of stiff 

 paper or cardboard to cover the sur- 

 face of the plaster inside the bottle. 

 Care must be exercised to keep the 

 bottles closed at all times as the air in 

 them is poisoned. 



2. Collect insects of all kinds and 

 in all places possible. Put the live 

 insects into a poison bottle and keep 



;LT4^ 



collection. one on the left may be used for water insects 



3. Pin insects according to the with some water plants growing in the bottom 



usual custom, the pin passing" through 

 a littie to the right of the central line. 

 The pin should be thrust through until only one-quarter of an inch remains 

 above. The best insect pins are very long and have small heads. Pinning 

 boxes or cases may easily be made of cigar boxes by gluing in the bottom of 

 each a layer of corrugated pasteboard, having a smooth surface, on top. The 

 pins holding the insects may be thrust into this corrugated paper. Always 

 arrange insects in groups according to relationships beetles in one box, moths 

 in another, flies in another, grasshoppers and locusts in another, and so on. 



4. Classify and name the insects in the collection, using Comstock's 

 Manual of Insects or other guides. 



5. Collect cocoons from trees, shrubs and other places. Put these in paste- 

 board boxes provided with ventilation holes and provided with rough sticks 

 on which the emerging moths may climb when they develop in the spring. 



6. Examine rapid development of wing surface of a large moth just 

 emerging from its cocoon. Note the wonderful rapidity and the conditions 

 under which the insect seems to develop best with wings hanging down ward. 



7. Find clusters of eggs of potato beetles, butterflies, grasshoppers, squash 

 bugs, and others. Put these into boxes or cages (Fig. 285) or keep the leaves 

 on which they may be found fresh in glasses of water until the larvae hatch 

 from the eggs. Development studies of this nature are always interesting 

 and instructive. 



