COMMON OBJECTS WORTH EXAMINING. 281 



a needle, and then cut off close to its point of attach- 

 ment. It is composed of two longitudinal parts which 

 separate easily. Examine in water or Canada balsam, 

 and notice the one or more rows of little projections 

 forming conspicuous barrel-shaped objects on the tip of 

 some butterflies' tongues. These are supposed to be 

 either papillae of taste or implements with which to 

 tear open the nectar glands within the flower. 



6. EGGS OF INSECTS cannot always be obtained when 

 wanted, but they make beautiful objects. They should 

 be viewed as opaque bodies, unless they are found after 

 the larva has escaped, when they may be transparent 

 and can be examined in water. The surface markings 

 are in a great variety of patterns. 



T. INSECTS, if small, are to be examined alive and as 

 opaque objects. They may be imprisoned in a deep 

 cell with a thin cover above them. If the cover tends 

 to slide off when the microscope is inclined, allow a very 

 small drop of water to run under one corner ; the capil- 

 lary attraction will then hold it in place. The quantity 

 of water must not be sufficient to extend into the cell. 

 If the insect is very small it may be killed by an im- 

 mersion in a very strong solution of carbolic acid, and 

 then transferred to Canada balsam, as described in the 

 books devoted to microscopical mounting. This treat- 

 ment often renders the body beautifully transparent, 

 forcing out the probosces and spreading the legs in a 

 very satisfactory manner. 



8. GIZZAEDS. Pull off the head of a common cricket 



