COMMON OBJECTS WORTH EXAMINING. 279 



also a scale-bearer. The abundant Lepisma saccharina, 

 a little, flattened, fish-shaped, silvery creature, often seen 

 running about old books, is covered with scales which 

 were at one time used as test objects. They may be 

 obtained by tapping the animal against a slide, or by 

 scraping the surface gently. All scales may be exam- 

 ined and mounted dry. A small piece cut from the 

 wing of a butterfly and viewed as an opaque object, 

 will show the arrangement of the scale-like feathers, a 

 sight well worth seeing. 



2. ELYTRA. The hard wing-covers (elytra} of beetles 

 are often of startling beauty when examined with a 

 strong light as opaque objects. They are not transpar- 

 ent, and cannot be made so, consequently only the sur- 

 face can be viewed. They are to be examined and 

 mounted dry. 



3. INSECTS' FEET vary greatly in appearance and struct- 

 ure. They afford an endless supply of the most inter- 

 esting objects. They should be cut off with sharp scis- 

 sors, so as to include part of the leg, and examined in 

 water. If the air clings to the bristles on the leg, dip 

 the latter into a drop of alcohol and transfer it to the 

 water on the slide before the alcohol evaporates. The 

 feet of the two or three kinds of flies that frequent our 

 houses, the feet of spiders and those of caterpillars, 

 should not be overlooked by the beginner. Spiders can 

 be obtained at all seasons, even in the winter, by search- 

 ing the dark corners of the cellar where the furnace is. 



4. EYES OF INSECTS should be viewed as opaque ob- 



