MOUNTING THE "SAW" OF THE TENTHEEDINID^. 325 



a colored ring can be put round the top object-glass by the turn-table 

 in the ordinary way, but, except for ornament, is not necessary. 

 The author usually prepares two or three dozen of the cards with 

 one cover-glass on at a time, so as to have them ready for use. The 

 object of letting the di-sections harden in the cell, half filled with 

 balsam, is that Inree or four separate parts may be arranged in the 

 most suitable way in the same cell without fear of their being disar- 

 ranged or injured when the top cover-glass is put on, while both 

 might happen if the whole operation was performed at once. 



For the examination of the saws, a quarter-inch objective is the 

 best; the teeth, in some cases, are so fine that they are apt to be over- 

 looked if lower powers are used. (Trans. Eutomol. Soc. Lond., 1881, 

 pp. 576-7.) 



