10 AMERICAN MUSEUM GUIDE LEAFLETS 



is to slip a lantern globe over it, sinking the bottom far enough in 

 the ground to prevent the escape of larvae in that direction and cover- 

 ing the top with cheesecloth. Even if the plant cannot be grown, twigs 

 can be kept fresh for some time by keeping their cut ends in a small 

 bottle of water sunk in the ground and used inside a lantern globe. 

 (See Fig. 3.) The twigs will be held in place and the larva- prevented 

 from drowning if cotton be loosely stuffed in the neck of the bottle 



Figure 4. Section of a plaster breeding box. a, Space for insects; 6, Space for water. 

 The broken line represents a glass plate. 



around the twigs. It is well to throw a thin layer of dirt over the 

 cotton so that fallen larvre can easily get back to their food. A 

 useful device for certain larvae (not leaf eaters) is shown in Fig. 4. 

 It is made of plaster of Paris. The water at one end keeps the 

 block moist. It is useful chiefly for ground-inhabiting larvae or 

 for galls. However, for the latter fruit jars with moist sand or a 

 moist sponge in the bottom do just as well or better. Do not forget 

 the larvae living in hollow stems, dead wood and under bark. 



KILLING 



Up to this point but little mention has been made of killing in- 

 sects and that was not really necessary. Insects can be studied alive 

 with great pleasure and profit. However, there are so many kinds 

 (about 15,000 in the vicinity of New York City, for example) and 

 the differences between species are often so minute that it is well to 

 kill and preserve 'samples at least. Fortunately this can be done with 

 less trouble and less injury to the balance of Nature than is the case 

 with most animals or even plants. Furthermore the collection can be 

 made ver}^ attractive and instructive without taking up much space. 



