PRESERVING 189 



position, as in the other. This board is best for insects having 

 on the back tufts of scales or of hairs that should not be 

 depressed. 



Proper spreading of the wings of little moths is something 

 of an art; the wings must be symmetrically placed. A hooked 

 pin point is often useful in drawing them into position. The 

 fine colors of the wings of butterflies and moths are in the 

 scales, and these must not be rubbed off. 



A drying box with shelves on which spreading boards may 

 be placed, and with ventilating windows covered with fine 

 meshed wire cloth to keep out museum pests, is a convenience 

 that any manual training department can provide. Spread 

 specimens must be left on the boards until thoroughly dry 

 (a week, perhaps); for if removed too soon, the wings will 

 droop. 



Cases for pinned specimens are made with soft bottoms to 

 receive the pins; and if the specimens are to be seen without 

 being handled, they should also have glass tops. They should 

 be made tight, and pest-proof.* 



Preservation on slides. Some insects are so minute and so 

 fragile that they are best preserved by being mounted in bal- 

 sam on microscopic slides. The mouthparts and other small 

 appendages of most insects are so small that when prepared 

 for critical scientific study they are best mounted in this 

 way. The method is so simple that any one can learn to 



* If pests get in, the sign of their presence will be a brown dust falling 

 on the bottom of the box beneath the specimens. They may be killed with 

 carbon bisulphide. Stick a bit of sponge on a pin ; saturate it with carbon 

 bisulphide; stick the pin in the box and close it up tight. 



